On October 19, 1973, a Friday, it became clear that the Justice Department’s special Watergate prosecutor, Archibald Cox, would not obey President Nixon’s order to be content with the summaries of recordings of Nixon and White House aides. Cox wanted the tapes, and it was easy to see that his defiance, or courage, was not going to lead to a happy conclusion. When a reporter asked Cox, on his way out of the office that night, if he intended to resign, Cox replied, “No—hell, no.”

The next day, though, he left, not of his accord: Nixon announced that he was abolishing the office of the Watergate prosecutor, and that its work would be transferred to the Justice Department. (A spokesman said that it would be “carried out with thoroughness and vigor.”) The Attorney General, Elliot L. Richardson, resigned when he was informed that Cox, whom he’d appointed, would be dismissed. The White House chief of staff, Alexander Haig, then told the Deputy Attorney General, William Ruckelshaus, to fire Cox, informing him, “Your Commander-in-Chief has given you an order.” Ruckelshaus resigned, too, and Robert Bork, the Solicitor General, in the order of succession, became the acting Attorney General—at which point the order to fire Cox was carried out. Bork also told the F.B.I. to seal the offices of the special prosecutor, which made the events of that evening—quickly dubbed the Saturday Night Massacre—sound very much like a domestic coup d’état, although it was nothing of the sort. Rather, although it was difficult to see clearly at that moment of drama and excitement, it became a test of the central issue raised by Cox, on his way out: “Whether we shall continue to be a government of laws and not of men is now for Congress and ultimately the American people.” All at once, there was talk of drastic measures; the Times columnist Anthony Lewis noted that “even Congress, which so often rolls on its back like a spaniel, is beginning to face the necessity of impeachment.”

It is natural to compare the dismissal of Cox, and the refusal by Richardson and Ruckelshaus to do the deed, to the firing of James Comey, the F.B.I. director, carried out by Trump’s Attorney General, the all-too-willing Jeff Sessions, if only because the dismissals, in both cases, were accompanied by a powerful odor: of something being covered up, along with a fear that what Americans treasure most—the values contained in the Constitution, the idea that America is indeed a nation of laws—were being undermined by the very people entrusted with protecting those values. In the Nixon era, the corruption, encouraged by the White House, was aimed at perceived enemies of the Administration. In a time so short that it doesn’t quite deserve to be called the Trump era, the current corruption includes possible attempts by a foreign power, Russia, to influence and subvert an American election. The odor this time includes the curious behavior of Trump and others in reacting to reliable information that General Michael Flynn, Trump’s national-security adviser, had lied about his preëlection contacts with the Russians. Was Comey getting close to something more? That’s a natural suspicion in a time when conspiracy theories, many of them promoted by Trump and his followers, have become so commonplace.

But the situation today is far more problematic and dangerous than the one facing the nation forty-four years ago. Nixon, for all his misdeeds, understood the Presidency, and the demands of his job. He was fascinated by history, and the geopolitics of his world, and understood both. In foreign policy, if he didn’t always act wisely, he acted consistently; it’s inconceivable that he would have found himself in the incoherent foreign-policy muddle in which Trump has put himself in the case of North Korea, with its threatening nuclear stockpile, and South Korea, which has just elected a new leader who doesn’t want a war.

At the end, in the Nixon White House, there was a sense of things going wrong—a little screwy, in fact—an anxious, fearful mood that came from the top, not unlike what is said to prevail in the Trump White House. As the Watergate scandal grew in intensity, the White House counsel, Leonard Garment, began to see Nixon “as a climbing man, scaling his way up, rung by rung, agonizingly, and then finally making it and then realizing that he didn’t belong there,” Garment told me. It’s hard to imagine what Trump, a reality-show host and real-estate promoter, feels when he looks down from his current perch at a world that, with his limited knowledge and experience, he can’t possibly grasp.

On October 19, 1973, the former Nixon White House counsel John Dean pleaded guilty to conspiracy to cover up the Watergate affair, and agreed to become a witness for the prosecution—for Cox. On Tuesday, Dean reflected on the Comey firing and told my colleague Jane Mayer, “I’d have thought they’d have let the man walk out under his own power. But Trump, I guess, always has to play the strong guy."

“By doing this, though,” Dean continued, “they’ve raised so many questions. How can you conclude anything but that Trump knows he’s got problems? . . . Every move they make keeps signalling ‘coverup.’ ”

Dean continued, “If they think they can influence the Russian investigation by removing Comey, they are naïve. I learned from my own experience that you can’t put in the fix by removing somebody.”