♪ ♪ NARRATOR: In the nation's capital during the middle decades of the 20th century, a joke was making the rounds about a luckless mother who had two grown sons, neither of whom was ever heard from again.

One was lost at sea.

The other became vice president.

♪ ♪ It's this weird situation with the vice presidency, where you're the running mate, you're the other face on the political campaign button, but unless the president of the United States wants to give you something to do, you can basically sit around twiddling your thumbs.

It's historically seen as a political death sentence.

RACHEL MADDOW (chuckling): Nobody in the history of America, nobody in the history of the world, has ever looked at themselves in the mirror and said, "If I do everything right, someday I'll be vice president."

NARRATOR: And yet the vice president has been key to the continuity of government since the early years of the republic.

And were a bookie to calculate the odds of a vice president succeeding to the presidency, rather than being elected to it, they would shake out at roughly one in five.

JARED COHEN: Eight times in history, a U.S. president has died in office.

One time in history, a president has resigned.

There were at least 19 times in history where the president of the United States was almost assassinated, almost died of illness, and almost died due to accident.

So it's sort of shocking to me that, despite that history, we don't pay more attention to the seriousness of the office.

♪ ♪ NARRATOR: When the clock started on that infamous Friday, the 22nd of November 1963, no one could see what was coming or the way the events of that morning would focus attention on the American vice presidency.

But in the recollection of Lady Bird Johnson, the vice president's wife, it began with the clouds parting.

LADY BIRD JOHNSON: After a drizzle in the morning, the sun came out bright and beautiful.

We were going into Dallas.

REPORTER: The president's plane now touching down, and the president and Mrs. Kennedy have arrived at Dallas Love Field.

(crowd cheering) Vice President and Mrs. Johnson are stepping to the foot of the ladder.

A reception line has formed, and there is Mrs. Kennedy.

The first lady is stepping from the plane.

LADY BIRD JOHNSON: In the lead car, President and Mrs. Kennedy.

And then a Secret Service car full of men.

And then our car.

REPORTER: There are hardly any clouds in the northern skies, and the president will be riding in the open.

LADY BIRD JOHNSON: The streets were lined with people, lots and lots of children, all smiling.

We were rounding a curve, going down a hill.

Suddenly, there was a sharp, loud report.

A shot.

And then two more.

♪ ♪ I heard over the radio system, "Let's get out of here."

(sirens blaring) And our Secret Service man who was with us vaulted over the front seat on top of Lyndon, threw him to the floor, and said, "Get down."

♪ ♪ NARRATOR: Pinned down in the back seat, Vice President Lyndon Johnson had no visual of what was happening, only the sensation of picking up speed.

REPORTER: It appears as though something has happened in the motorcade group.

Stand by just a moment, please.

There has been a shooting, I repeat, a shooting in the motorcade in the downtown area.

Parkland Hospital has been advised to stand by for a severe gunshot wound.

REPORTER 2: And the first unconfirmed reports say the president was hit in the head.

REPORTER 3: A priest has been ordered; emergency supplies of blood also being rushed to the hospital.

♪ ♪ NARRATOR: As of that grim morning, Johnson had been vice president of the United States for two years, ten months, and two days, and by his own account, he had "detested every minute of it."

President Johnson was what he'd had in mind-- an ambition first announced at 17 or so, then doggedly pursued straight into the halls of Congress.

He'd been elected Senate minority leader at 46 and majority leader the following year, the youngest man ever to hold that post.

By 1960, he wielded so much power in Washington that he'd waited until the very last minute to declare his candidacy for president, expecting to best the primary favorite, John Kennedy, in the backrooms at the Democratic National Convention.

(crowd cheering) But that had proved a serious miscalculation.

REPORTER: And on the balloting, it's a Kennedy landslide.

MAN: Mr. Chairman, Wyoming's vote will make a majority for Senator Kennedy.

(crowd cheering) NARRATOR: With no shot at the top of the ticket, Johnson had settled for running mate, persuaded the Democrats could not win the election without him.

♪ ♪ The vice presidency was for Johnson, as for so many who had held the office before him, a consolation prize without consolation.

Denied an office in the West Wing and a seat on Air Force One, disdained by Kennedy's urbane inner circle, who snidely referred to the Texas-born VP and his wife as "Uncle Cornpone and his Little Lamb Chop," Johnson had become, as one observer put it, "a man without a purpose; a great horse in a very small corral."

Are you familiar with the name Lyndon Johnson?

No.

Pardon me?

No.

No?

No.

No, sir.

No?

He's not president.

JAMES HITE: John Kennedy knew Johnson was a restless person, and he assigned him to some, you know, sort of mediocre commissions and different things, you know, just to kind of keep him busy.

And he also turned Johnson into a roving diplomat, traveling around the world and meeting with world leaders.

I think Kennedy's attitude was that he didn't really need the vice president nearby.

He didn't need the vice president involved in the day-to-day business of the administration.

NARRATOR: If Johnson gamely played his part, he did so knowing it was only a show.

"The vice presidency is filled with trips around the world, "chauffeurs, men saluting, people clapping, chairmanships of councils," he once said.

"But in the end, it is nothing."

Standing with his wife now, though, in a close, curtained-off room at Dallas's Parkland Hospital, his office suddenly took on a new cast.

LADY BIRD JOHNSON: I think it was from Kenny O'Donnell that I first heard the words, "The president is dead."

COHEN: I think LBJ is contemplating and trying to make sense of a lot of things that are happening very fast.

He's about to get the job that he's always wanted, but this isn't how he wants it.

From Dallas, Texas, the flash apparently official: President Kennedy died at 1:00 p.m. Central Standard Time, 2:00 Eastern Standard Time, some 38 minutes ago.

Vice President, either soon-to-be or already President of the United States Lyndon Johnson was at the Parkland Hospital in Dallas at the time or near the time of the official announcement of the death of the 35th president of this country, John F. Kennedy.

The Secret Service at this moment, or as of a few moments ago, was saying that Mr. Johnson's whereabouts would not be revealed for security reasons.

SARAH T. HUGHES: ...I do solemnly swear... LYNDON JOHNSON: ...I do solemnly swear... HUGHES: ...that I will faithfully execute... LYNDON JOHNSON: ...that I will faithfully execute... NARRATOR: "I knew it was imperative that I grasp the reins of power and do so without delay," Johnson remembered.

"The nation was in a state of shock and grief.

"The entire world was watching us through a magnifying glass.

I had to prove myself."

I will do my best.

That is all I can do.

I ask for your help and God's.

♪ ♪ NARRATOR: It was a paradox of the vice presidency that the first to hold the office, John Adams, had been quick to grasp.

As he had put it: "I am the vice president.

"In this, I am nothing.

But I may be everything."

Good evening.

History has been trying to tell us something about the vice presidency.

The office was added as an afterthought to the Constitution, which as a document has been called the most wonderful work ever struck off by the brain and purpose of man.

But by the time the founding fathers got around to the vice presidency, they were weary and impatient.

And the flaws of their haste have haunted us ever since.

NARRATOR: The U.S. Constitution assigned precisely two responsibilities to the vice president, a job description so slight that a member of the first Congress suggested the position be compensated on a per diem basis.

KATE ANDERSEN BROWER: The vice president really has two roles: to be there in case something happens to the president, to stand in for him, take his place, or, uh, cast a tie-breaking vote in the Senate.

The founding fathers really didn't give the vice presidency much thought.

COHEN: They thought even less about succession.

I think that's fascinating, because people didn't live that long back then.

The Constitution said, "In case of the removal of the president "or his death, resignation, or inability "to discharge the duties of said office, the same shall devolve on the vice president."

They left it very vague what "devolve" meant and what "same" meant, what they meant by "inability to discharge the duties."

They didn't leave much of a blueprint.

NARRATOR: Under the framers' original scheme of election, the vice president was to be the literal runner-up, the winner of the second-most electoral votes for president.

But the rise of political parties and the prospect of ideological opponents serving in tandem made that approach untenable, and in 1804 helped to spur the 12th Amendment.

HITE: What the 12th Amendment did is it created a method whereby electors were to cast separate votes for president and separate votes for vice president.

Under the original method, you had a field of candidates who were generally of presidential caliber.

You, you were taking a shot, and there was a good chance that you could end up president.

After the 12th Amendment, because the vice presidency lacked any substantive powers, there began to be a decline in the number of and the quality of candidates who would stand for vice president.

You would be hard-pressed to find very many Americans who could name vice presidents from the 19th century.

RAMESH PONNURU: Vice presidents were really chosen by political party organizations.

Many times, the president was chosen because he was part of the winning faction, and the minority faction was given the vice presidency often as a way of keeping the party together.

That tradition continued even after it became much more of a presidentially selected position, because those presidential candidates themselves had an interest in some kind of balance.

NARRATOR: During the first half-century of the new republic, no president died in office, and the succession clause went untested.

Then, in 1841, the ninth commander-in-chief, William Henry Harrison, succumbed to pneumonia barely a month after his inauguration, and Vice President John Tyler stepped into the breach, boldly declaring himself president of the United States.

JOEL K. GOLDSTEIN: His claim was controversial, because many people read the Constitution, which was ambiguous, to say that if the president died, the vice president simply acted as president, that he simply exercised the powers and duties of the presidency while remaining vice president.

But Tyler insisted that he was president, refused to be dealt with on any other basis.

COHEN: He was subsequently referred to as "His Accidency," "The Great Usurper"... You know, the press had a field day with it.

He would often get mail addressed to "John Tyler," comma, "acting president of the United States."

And he had a rule of thumb that he would return those unopened regardless of who they came from.

♪ ♪ The Tyler Precedent took care of what happens when the president dies in office, albeit not formalized by the Constitution.

Seven subsequent presidents became president of the United States because of that precedent: Millard Fillmore, Andrew Johnson, Chester Arthur, Theodore Roosevelt, Calvin Coolidge, Harry Truman, and Lyndon Johnson.

NARRATOR: The vice presidency, meanwhile, would remain vacant in each case for the duration of the term, there being no constitutional mechanism for filling such a vacancy.

Twice between 1842 and 1963, Congress revised constitutional provisions that extended the line of succession beyond the vice presidency.

But the man first in that line, the vice president, remained a kind of appendage, his prerogatives shrouded in mystery so long as the president was alive.

In 1881, after President James Garfield was struck by a would-be assassin's bullet, he clung to life for an agonizing 88 days, while Vice President Chester A. Arthur hovered on the sidelines, unsure of his authority to step in.

GOLDSTEIN: There was a concern that if anyone acted to transfer power to Vice President Arthur, that it would displace Garfield from the presidency because Arthur, like Tyler, would become president.

And since the Constitution only envisions one president, that would mean that Garfield would be ousted.

So this became sort of a cloud that hung over, um, the country, really, whenever there was a presidential inability.

NARRATOR: When Woodrow Wilson suffered a stroke in 1919, his VP, Thomas Marshall, likewise refused to appear the usurper, and stood aside as Wilson's wife and his secretary kept the president's condition a secret for more than six months.

And then there was Richard Nixon, vice president to Dwight D. Eisenhower, who spent much of his presidency in and out of the hospital.

MADDOW: So in 1955, General Eisenhower is very, very popular as a president, but he has a massive heart attack, which requires a very long convalescence.

Then in 1956, as he is standing for reelection, he has emergency surgery, which also requires a very long convalescence.

And it opens up discussion around this black box, which was who was running the presidency while Ike was convalescing after his multiple serious health problems.

COHEN: There was no provision in the Constitution for dealing with a situation where the president is disabled.

There's actually no formal mechanism for discharging the duties of the president to an acting president, even the vice president.

There was no clarity around who's in charge.

♪ ♪ GOLDSTEIN: People increasingly looked to the president to address both domestic and international problems and to handle an increasingly complicated global situation in a nuclear age.

I expect to be back at my accustomed duties, although they say I must ease my way into 'em, and not bulldoze my way into 'em.

GOLDSTEIN: It made the president more powerful, more significant.

And that meant that the vice president became more significant.

And so ultimately, the vice presidency gets pulled from Capitol Hill, where the vice presidents had presided over the Senate and done really little else, down Pennsylvania Avenue to the executive branch.

President Eisenhower was cognizant and very transparent, really, that he had health issues.

He had concerns about the lack of clarity in the Constitution in terms of inability, or presidents being incapacitated for some period of time.

And so he gave himself the authority to decide when an inability existed.

And even more important than that, this same directive, he gave that authority to Vice President Nixon to decide if the president was incapacitated or unable to fulfill the duties of the office.

But it didn't have the force of law.

MADDOW: It was polite and unstressful, apparently, between them, but it was really precarious for the country.

What if there had been a dispute as to whether or not the president was disabled and the vice president thereby enabled?

What if the president and the vice president disagreed about that?

It did put the issue of when and how and whether the vice president is running the country front of mind.

♪ ♪ NARRATOR: The gentlemen's agreement made between Eisenhower and Nixon had been replicated by John Kennedy and Lyndon Johnson.

But there was little reason to think they would need to invoke it.

As Kennedy had put it to an aide during the campaign, "I'm 43 years old.

"I'm the healthiest candidate for president.

And I'm not going to die in office."

JOHN D. FEERICK: In 1963, I was a young lawyer.

I had spent the previous two years writing an article for the "Fordham Law Review."

I started when I saw newspaper articles about disability during the Eisenhower administration, and I took that on as my topic.

And it was published a month before President Kennedy's assassination.

And I figured, well, it's probably going to go on a library shelf somewhere, but it's an important subject.

♪ ♪ When President Kennedy was assassinated, all of a sudden, I got all kinds of calls: Can we get your article?

Would you be on a program?

Now therefore, I, Lyndon B. Johnson, president of the United States of America, do appoint Monday next, November 25, the day of the funeral service of President Kennedy, to be a national day of mourning throughout the United States.

COHEN: The assassination of John F. Kennedy and the subsequent elevation of Lyndon Johnson was different than any of the seven deaths in office that had happened before, in part because it was so dramatic.

The president of the United States was shot on live TV.

And then the alleged assassin was shot just a couple days later, also on live television.

It traumatized an entire generation.

MADDOW: President Kennedy was shot in the head.

Had he survived but been disabled, was the country comfortable leaving it up to one man's say-so, to his vice president, Johnson's say-so, as to whether or not President Kennedy was able to continue in the office of the presidency?

♪ ♪ COHEN: Back in the late 1700s and early 1800s, perhaps the question of succession didn't matter as much as it does in the age of nuclear weapons.

But we're in the height of the Cold War.

The Cuban Missile Crisis has happened.

Um, you just can't live in a world with ambiguity around succession.

♪ ♪ HITE: Vietnam was moving forward.

There were civil rights protests.

You had civil rights leaders being assassinated.

And so there was a growing awareness, like, this is a dangerous world, and mortality is a major factor here for presidents.

This is real, this happens, and it happens pretty frequently.

All I have I would have given gladly not to be standing here today.

NARRATOR: When President Johnson delivered his special message to Congress on November 27, 1963, five days after the assassination, there was more than usual interest in the politicians seated behind him on the dais: to the left, the Speaker of the House, a 72-year-old with very little international experience, and the 86-year-old president pro tem of the Senate on the right.

Should something untoward happen to the president now, these men were the next in line.

The constitutional flaw that had gone unmended for nearly two centuries was suddenly now at the top of the national agenda.

ANNOUNCER: "CBS Reports: The Crisis of Presidential Succession."

I think that now is the time to, for all of us to study it very intensively.

We've just had this great tragedy.

We came out of our state possibly of shocked disbelief.

But now it is time to do something that common sense determines is the best way to keep our government functioning without the possibility of great, great confusion right in the point of crisis.

(plane engine roars) NARRATOR: It was while taxiing toward the terminal at Chicago's O'Hare that Birch Bayh, the freshman senator from Indiana, first heard that Kennedy had been shot.

The pilot had come over the intercom.

Later, Bayh would recall that as his taxi crawled through the city's streets that evening, "bleak with rain and sorrow," he said, his thoughts had gone to Lyndon Johnson, to the counsel he'd been so well-suited to provide as vice president, and the counsel he surely would need from his VP in turn.

"But there I sat up sharply," Bayh remembered.

"There was no vice president now."

In fact, as of that moment, the nation had been without a vice president for a cumulative total of more than 36 years.

COHEN: The fact that we had so many moments in history where there was a vacancy in the vice presidency tells you how little we thought about the importance of the vice presidency.

But to not have a provision to replace the vice president creates a significant break in the line of succession.

♪ ♪ NARRATOR: As it happened, Senator Bayh recently had been made chairman of the Subcommittee on Constitutional Amendments, an appointment now ripe with purpose.

Just 20 days after Kennedy's assassination, Bayh announced that his subcommittee would hold hearings on the twinned problems of presidential succession and inability, and proposed a constitutional amendment, Senate Joint Resolution 139, meant to address both.

The American Bar Association played a very important role in the creation of the amendment, and I was given an opportunity to participate in that.

The issue boiled down to, how do we deal with an involuntary inability?

That the president is... there's something wrong.

We have to address it, and what should those provisions be?

NARRATOR: Presidential inability had been a preoccupation on Capitol Hill at least since the Eisenhower administration.

A raft of remedies had been proposed and hearings held, but consensus proved elusive.

As the chairman of the House Judiciary Committee, Emanuel Celler, put it, "When you had three congressmen discussing inability, you had 17 different opinions."

MADDOW: When they were debating the circumstances in which a vice president would take over and become, effectively, acting president, it was like an imagination debate.

Imagine all of the crazy things that might befall a president.

And once you start talking about things in those terms, you're unlikely at any point for everybody to arrive at an idea that seems like something to handle all contingencies.

NARRATOR: It took Bayh 18 months to push his resolution through both houses of Congress and another 16 for it to be ratified by the states, before it was finally and formally proclaimed the 25th Amendment to the U.S. Constitution.

I think it's a happy announcement that today, on the tenth day of February 1967, we can announce the consummation of efforts to find a solution to a constitutional gap which has existed for the best part of two centuries.

NARRATOR: Broad consensus at last had emerged on one crucial point: the nation needed a vice president at all times.

Today, in this crisis-ridden era, there is no margin for delay, no possible justification for ever permitting a vacuum in our national leadership.

And now, at last, through the 25th Amendment, we have the means of responding to these crises of responsibility.

GOLDSTEIN: The 25th Amendment created a means of filling a vice presidential vacancy during a presidential term.

♪ ♪ Also to transfer power to the vice president on a temporary basis if the president was unable to exercise presidential power.

It really reflected a new vision of the vice presidency as a important officer in the executive branch, a close and compatible colleague of the president, someone who was familiar with the policy and committed to the policies of the administration so that a transfer of power would go smoothly.

(applauding) FEERICK: Even if a president had to have a one-hour operation, as Senator Bayh would say, if missiles were flying at America at that point, you want to be sure that there's no gap in terms of where the executive power is, and the person that we have to look to in that situation is the vice president.

♪ ♪ NARRATOR: Few observers thought the amendment perfect, but most agreed it was flexible enough to cover all manner of contingencies.

What no one could have guessed was just how, and how often, it soon would be called into play.

They were trying to imagine everything, but truth is always stranger than fiction, right?

The, the real circumstances of how things come to pass are always wilder than the hypotheticals that you imagine.

And so it was with the vice presidency, and so it was with the 25th Amendment.

♪ ♪ NARRATOR: When it was first reported in the late summer of 1972, the Watergate story might easily have escaped notice: an odd break-in at the headquarters of the Democratic National Committee involving five men, a bagful of sophisticated surveillance devices, and 230 crisp $100 bills.

Then it became clear that one of the Watergate burglars had ties to the reelection campaign of President Richard M. Nixon, and the nation's attention was riveted as, month by month, evidence mounted of a White House conspiracy and cover-up.

By the middle of July 1973, investigators were focused on tape recordings of conversations had in Nixon's offices-- recordings that Nixon patently refused to release on the grounds of executive privilege.

The Senate Watergate Committee met and unanimously voted to subpoena the tapes.

MADDOW: So in 1973, the Watergate political crisis is in full flower.

The attorney general, Elliot Richardson, is worried not only that the president might have committed crimes, that the president might be removed from office, he's worried that the president might die, he's under so much stress.

And at the same time, in the summer of 1973, this U.S. attorney's office in Maryland keeps calling and asking for a meeting.

And they finally get the news through to him that this little public corruption investigation that they've been working on in Maryland has produced very good evidence that Vice President Agnew has been committing extortion and taking cash bribes in the White House.

Washington was stunned today by the disclosure that Vice President Agnew is under criminal investigation by federal authorities in his home state of Maryland.

MADDOW: Imagine you're Richard Nixon in this moment.

Watergate is spiraling and spiraling, and getting worse and worse, and threatening you more and more with each passing day.

Now, here's your vice president taking bribes, taking envelopes stuffed with $100 bills during the time he was vice president.

I will fight to prove my innocence and that I intend to remain in the high office to which I have been twice elected.

(cheering and applauding) MADDOW: Spiro Agnew was chosen by Richard Nixon as his running mate in 1968, and it was a bewildering choice to most observers.

Spiro Agnew was the governor of Maryland and he was not a high-profile member of the Republican establishment in any way.

That said, during his vice presidency, he really established himself as a political force, as a divisive, rabble-rousing figure who antagonized the press, who excited the right-wing base of the Republican Party.

(chanting, clapping) MADDOW: When Nixon and Agnew ran for reelection in 1972, that proved to be a really winning combination.

It was a landslide when they won in '72.

NARRATOR: But Agnew had never been invited into Nixon's inner circle.

Though he'd been given an office in the West Wing-- the first vice president to be so situated-- he'd been made to understand that his proximity to the Oval was purely symbolic.

"A little over a week ago, I took a rather unusual step for a vice president," Agnew complained in his memoir.

"I said something."

Before very long, his West Wing perch had been repossessed.

Then came the glare of simultaneous scandals in the executive branch.

REPORTER: "Time" magazine today quotes officials in the Department of Justice as saying that the case against Vice President Agnew is growing steadily stronger and that an indictment appears inevitable.

♪ ♪ HITE: Nixon refused to support Agnew or defend Agnew in any way.

He knew it was likely that he himself would be impeached or forced to resign, knew that it would be a disaster if Agnew were to succeed to the presidency.

So Nixon's Justice Department was actively pursuing forcing Agnew from office.

AGNEW: I will not resign if indicted.

I will not resign if indicted.

(cheering and applauding) I intend to stay and fight.

(crowd cheers and applauds) MADDOW: What Attorney General Elliot Richardson decided to do was allow these federal prosecutors to go ahead with the plan to bring federal criminal charges, dozens of felony charges, against the sitting vice president of the United States.

And when Vice President Agnew was informed that that was what was going to happen to him, he entered into a plea deal discussion.

Very unusually, it was supervised by the judge himself.

Even more unusually, the judge supervised the plea deal discussions at a motel.

I don't know.

That's what they did-- they met at a motel.

The two sides sat on opposite twin beds in a motel room with a judge.

They worked it out.

And what they worked out was that Vice President Agnew would not go to prison.

He would be assured that he would not go to prison.

He would have to plead, essentially, no contest to at least one charge, but, as part of the agreement, he would resign the vice presidency.

Vice President Agnew, burying himself as a tax cheat, resigned today under an agreement which protects him from prosecution on charges of grafting.

The big question tonight, who will succeed Spiro Agnew as vice president?

REPORTER: We're talking about the 25th Amendment.

The Constitution providing that a vacancy in office is to be filled by a nominee proposed by the president, ratified by the Congress.

How is this thing going to work?

MAX ROBINSON: There are some questions to be answered, but I think we are extremely fortunate that there is the 25th Amendment to work with.

MADDOW: The existence of the 25th Amendment, and the clarity around how a vacancy in the vice presidency is filled, was, I think, part of the reason that Agnew's resignation was sort of an okay resolution to this crisis.

♪ ♪ NARRATOR: With the Watergate tapes still hostage to the president's claim of executive privilege, some in Congress now balked at the 25th Amendment and the prospect of having to confirm a vice president of Nixon's choice.

"So long as the president himself is so clearly under the cloud of possible disclosures on the tapes," insisted Senator Edward Kennedy, "grave questions exist as to the propriety of the president's choosing his own successor."

HITE: Richard Nixon was an embattled president, and yet, the authority given to him in the 25th Amendment allowed him to exercise considerable influence on the political landscape.

And so he immediately started looking for someone to fill the vacancy.

NARRATOR: In the end, his selection was a calculated one: the less overtly presidential the nominee, Nixon reasoned, the less controversial, the more likely a speedy confirmation by Congress.

I proudly present to you the man whose name I will submit to the Congress of the United States for confirmation as the vice president of the United States, Congressman Gerald Ford of Michigan.

(audience cheers and applauds) BROWER: He picks Gerald Ford, this ex-football player, very affable, very likable, but not somebody who was going to run for president.

He was actually thinking of retiring.

He was going to run one more time, he told his wife, and then hang it up.

COHEN: Gerald Ford was a obscure congressman from Michigan.

Richard Nixon offered him an opportunity to have the second-most powerful job in the country.

There's not a lot of instances where somebody might view the vice presidency as an upgrade, but from Michigan's fifth district, I'd say it's an upgrade.

♪ ♪ RON ZIEGLER: I know many of you are on deadline, so I have a brief statement to give you at this time relating to action which President Nixon has taken tonight.

♪ ♪ President Nixon has tonight... NARRATOR: On October 20, 1973, ten days after Agnew's resignation and two weeks before Ford's confirmation hearings were set to begin, President Nixon managed to hasten his own political demise.

In a fit of pique, he demanded that Archibald Cox, the special prosecutor investigating Watergate, be dismissed, his office abolished, and his files sealed-- an action that led, in turn, to the immediate resignation of, first, Attorney General Richardson, then his deputy.

The newspapers dubbed it "The Saturday Night Massacre," and cries for Nixon's ouster rose across the land.

Nothing like this has ever happened before.

And what it means is that the worst dreams of everyone who was worried about the president's secret tapes have now become true, become reality.

NARRATOR: Western Union reported that in the following three days, more than 150,000 telegrams flooded Washington, "the heaviest concentrated volume on record."

As one columnist noted, "Even Congress, "which so often rolls on its back like a spaniel, is beginning to face the necessity of impeachment."

In the Capitol Hill office of the Speaker of the House, the usually remote possibility of a double vacancy in the executive branch suddenly loomed large.

MADDOW: Here's Carl Albert, Democratic Speaker of the House, and two things land in his lap at the same time.

First of all, the vice president has resigned, which means Carl Albert has responsibility in the House for confirming a new vice president.

Simultaneously, Richard Nixon, the president, is going to be impeached, and Carl Albert has responsibility for dealing with the House side of the impeachment process.

And if there is no president and there is no vice president, who becomes president?

(laughing): Carl Albert, speaker of the House.

So if he wanted to, if he was of that kind of a mindset, Carl Albert in that moment could have engineered the ousting of the president of the United States, not filling the vice presidency of the United States, and thus installing himself as president.

Which would have put the presidency in the hands of the Democratic Party just months after the entire country had chosen the Republican Party to lead by a landslide.

It would've been a partisan coup.

It would've been legal, it would've been procedurally sound, and it would've been a revolution.

FORD: These are not ordinary times, nor, I suppose, will the times ever be ordinary when the 25th Amendment must be invoked.

NARRATOR: By the time Ford's confirmation hearings got underway, the likelihood that the vice presidential nominee ultimately would succeed to the presidency was on everyone's mind.

Never before was a candidate for national office subjected to such close scrutiny.

Some 350 FBI agents were dispatched from 33 different field offices to look into every aspect of Ford's life, while Ford himself patiently endured hours upon hours of questioning by members of both houses of Congress.

Today, having confirmed the nomination of Gerald R. Ford, the proceedings required by Section Two of the 25th Amendment to the United States Constitution have been complied with.

Raise your right hand, Mr. Ford.

Put your hand on the Bible.

NARRATOR: Confirmed swiftly and by overwhelming majority, Ford was sworn in on December 6, 1973, the 40th vice president of the United States.

He would spend fewer than eight months in the job before the U.S. Supreme Court ordered the long-disputed White House tapes released-- among them, three conversations that proved Nixon had been party to the Watergate cover-up.

♪ ♪ A day or two later, Ford went with his wife, Betty, to visit what was to be their new home: a dwelling authorized by an act of Congress shortly after the passage of the 25th Amendment, the first official residence ever provided to the vice president of the United States.

The Fords are the first family with the opportunity to live there, and they get this tour, and Betty Ford gets to pick out the china for the vice president.

And Gerald Ford turns to her and says, "Betty, we're not going to ever live here."

He saw the writing on the wall.

They were going to be moving into the White House.

I have never been a quitter.

To leave office before my term is completed is abhorrent to every instinct in my body.

But as president, I must put the interests of America first.

WALTER CRONKITE: The president of the United States leaves office, the first in our 189-year history to do so by the route of resignation.

HITE: The transition went remarkably well.

It was essentially seamless.

I think in part that is because the 25th Amendment had allowed there to be a procedure for filling vacancies in the vice presidency.

WARREN BURGER: Mr. Vice President, are you prepared to take the oath of office as president of the United States?

I am, sir.

HITE: The president was able to choose someone from his own political party, so there was no conflict that way.

Ladies and gentlemen, the president of the United States.

(audience applauds) HITE: And at the end of the day, Ford was in fact prepared.

He was in fact qualified.

My fellow Americans, our long national nightmare is over.

Our Constitution works.

Our great republic is a government of laws and not of men.

BROWER: Ford had never been on a presidential ticket.

He had never run for any office higher than this one little district in Michigan.

Suddenly, here he was, the most powerful person in the world.

♪ ♪ NARRATOR: It had all happened so quickly, the Nixons hadn't yet had the chance to move their belongings out of the White House.

BROWER: The Fords had this very sweet, middle-class, colonial house in Alexandria, Virginia.

Being the affable people they were, they gave the Nixons time to get their things out and make the transition and move.

And so there was a period of time there where the Fords were actually the president and first lady, living in their house in Virginia.

This was just a mere decade after JFK had been assassinated.

So you have this president living in a quiet suburban community outside of D.C.

So they had to put bulletproof glass in the master bedroom.

They had to reinforce the driveway with steel rods underneath for the president's motorcade cars to be parked.

They had Secret Service in the garage, setting up their post.

Ford said, "Our poor neighbors went through hell."

(applauding) NARRATOR: Once again, for the second time in just over a year, the vice presidency stood vacant, and the reality of the procedures outlined by the 25th Amendment had begun to sink in.

As one senator had foreseen even before Nixon resigned, "The nation will no longer be democratically governed."

PONNURU: Gerald Ford was the first president in U.S. history, and so far is the only president in U.S. history, to assume the office without having been elected president or vice president.

He had never faced a national electorate before, and yet he became president of the United States.

HITE: Adding even more to the whole oddness of the situation, if you will, was that the first task Gerald Ford had as president was to choose a new vice president.

REPORTER: So he comes through the door now with his choice.

And the choice, and this is... REPORTER 2: Nelson Rockefeller.

REPORTER 1: It is Nelson Rockefeller, the former governor of New York, who was leading the list of speculation among many people.

PONNURU: Nelson Rockefeller had been a leader of what was then a very strong liberal to moderate faction in the Republican Party.

He made serious bids for the presidency, although he had not won a Republican nomination.

And he was somebody who, as governor of New York, was a widely respected figure nationally.

Mr. President, the vice president-designate of the United States.

FEERICK: By the end of that year, we have two of our national officers, first and only time in the history of the country, who were appointed, so to speak, under the 25th Amendment.

But it worked.

I pledge myself to the fullest limit of my capacity to work with you, Mr. President, and the Congress in the great task of building the strength of America.

♪ ♪ NARRATOR: When Rockefeller took office on December 19, 1974, he assumed a position newly imbued with stature and significance.

For if the 25th Amendment had sidestepped democratic ideals in laying a path to the office, it also had established-- constitutionally and once and for all-- the importance of the second-in-command.

HITE: When Nelson Rockefeller assumed the vice presidency, it was a much-changed institution even from a few years prior, let alone historically.

When Richard Nixon was vice president, he had a staff, a small staff, and a budget of under $48,000 a year.

When Rockefeller became vice president, he had a staff of over 70 and a budget of $2 million.

The office of the vice president began to mirror the office of the president.

The vice president had special assistants on domestic and foreign policy, had a press secretary, had a chief of staff.

Those things may seem just symbolic, but they're not.

They imply power and they imply authority.

Whether the vice president then actually exercises power is a whole different story.

♪ ♪ MADDOW: Having that new constitutional amendment focused on the vice presidency, both implicitly acknowledging the importance of the vice presidency and also systematizing, um, the nature of the office, I think did underscore for the country that the vice presidency is a thing.

(chuckles) That it's not only a contingency, that it is an office that must be filled and that has an important role in the country.

GOLDSTEIN: Vice president has been a principal part of presidential decision-making in virtually every administration over the last 50 years.

Being vice president gives you opportunities to operate as a governmental official in ways that most high executive officials never experience.

♪ ♪ To take an office that for most of our history has been lampooned and to turn it into a consequential position is really one of the great modern successes of our system of government.

♪ ♪ NARRATOR: The office that Vice President John Adams occupied at the dawn of American democracy would be largely unrecognizable to him now.

More than two centuries on, it can no longer credibly be described as nothing.

But the vice president is still and always a heartbeat away from being everything.

♪ ♪ ANNOUNCER: "American Experience: The American Vice President" is available on DVD.

To order, visit ShopPBS or call 1-800-PLAY-PBS.

"American Experience" is also available with PBS Passport and on Amazon Prime Video.

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