In the throes of Watergate, Vice President Spiro Agnew was caught up in an unrelated corruption scandal. He pleaded guilty and resigned his office on October 10, 1973.

To that point, Agnew had served as a useful insurance policy for Richard Nixon, in the manner of the joke Charles II is sometimes reputed to have made to his even more unpopular brother when the latter warned him against plots. “Never fear James; they will not kill me to make thee king.”

Agnew’s replacement—former House Minority Leader Gerald Ford—faced an agonizing personal dilemma. Republicans were monitoring him suspiciously for any sign of disloyalty to Nixon, any tendency to hasten impeachment forward to enter the presidency himself. Democrats monitored him suspiciously, too. Scandals had already consumed two Nixon attorneys general and many other high officials. Could Ford keep clean?

Ford’s solution: He got out of town. Republicans were facing a tough election in November 1974, so Ford volunteered as their headliner of choice, their fundraiser in chief. As the Gerald R. Ford Presidential Library notes, during the 10 months of his vice presidency “Ford represented the administration by making over 200 formal speeches and traveling approximately 110,000 miles.”

Vice presidents traveled less comfortably in those days than they do now. In his candid memoir of traveling with Ford, the former Newsweek correspondent Thomas DeFrank vividly described the cramped small jets and propeller planes that typically served as “Air Force Two”—a phrase that began as a joke.

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Ford’s travels might have been controversial. In this moment of national crisis, a new vice president acting as such an eager partisan for a damaged party? But criticism was held back by the knowledge, shared by Democrats and Republicans alike, that America was going to need Ford. The country was going to need him to be clean, and the surest way to protect him was to keep him far from Washington. Ford’s intact reputation enabled Congress and the country to turn the page definitively in August 1974. Nixon’s most tainted appointees had been forced from office before him. When Nixon resigned at last, the government could reset and begin a new era.

Donald Trump may not know much of this history, but he intuits its lessons. From the beginning, he has appeared determined to implicate as many members of his administration as possible in his scandal—Vice President Mike Pence heading the list.

At a press conference at the United Nations on September 25, Trump delivered a warning message. “The word is, they’re going to ask for the first phone conversation. You can have it any time you need it. And also Mike Pence’s conversations, which were, I think, one or two of them. They were perfect. They were all perfect.”

Indeed, Pence seems to have been involved up to the eyeballs in the Ukraine plot. His team’s messaging—Yes, he pressed the Ukrainians to investigate corruption, but he never appreciated that Trump’s true purpose was to pursue the Bidens—fails the laugh test. Pence’s taint presents a political problem for him, but raises a much graver question for the country. If the Senate ever could muster the integrity to remove Trump from office, there would be no Ford to put in his place, only a vice president who participated in Trump’s dirty schemes, from staying at a remote resort to direct government funds to Trump’s failing Irish golf course to extorting an invaded country to fabricate political dirt to help Trump’s reelection.

Trump’s compromised attorney general remains on the job, as does his apparently compromised secretary of state. As the text messages from Gordon Sondland, Trump’s ambassador to the European Union, confirm, the corruption permeates Trump’s second- and third-level appointments, too.

Not only is this scandal worse than Watergate—the break-in at the Democratic National Committee offices did not betray the national-security interests of the United States—but the outlook for the country is worse, too. There is no easy exit from the scandal by removing the president. Nixon’s party broke with him after the release of the “smoking gun” tape in August 1974 removed any possibility of honest belief in Nixon’s innocence. Trump’s guilt has now passed that point—and Trump’s party protects him anyway.

Read more: God’s plan for Mike Pence

The political scientists can explain the structural reasons why the Republican Party has submitted to Trump, but structures are inhabited by people who make moral choices. The country needed Pence to keep himself clean, as Ford did, and instead—whether out of raw ambition or some weak personal impulse to subservience—Pence plunged into the deepest ooze of the mud. Maybe he struggled to keep his distance, maybe he obeyed only reluctantly, or maybe he eagerly volunteered to ingratiate himself with his crooked boss. That part of the story will all come out.

For now, all we need to say is that Pence betrayed his most important duty as vice president: Be ready to step into the nation’s highest office should the need arise. He’s as much a part of the problem as Trump is, and Pence’s personal choices ensure that the scandal of the century will continue to rip apart U.S. politics even if the impeachment process somehow succeeds.