On Tuesday, the epilogue to Trump’s rancid presidency begins. The post-presidency Senate impeachment trial, unique in the long annals of American presidential history, promises to be both spectacular political theater and also profoundly important for the future of American democracy—and, most immediately, for the future of the Republican Party. In this trial, the House impeachment managers, led by Representative Jamie Raskin, will argue that, far from being protected free speech, “President Trump’s incitement of insurrection was itself a frontal assault on the First Amendment,” in attempting to undo the free expression of America’s voters. They will argue that the president, by mustering a violent mob—under the guise of baseless “stop the steal” allegations—to assault the Capitol while Congress was certifying the Electoral College vote, was deliberately engaging in an effort to undermine the peaceful transfer of power; and that, having so thoroughly violated the Constitution that he had sworn an oath to uphold, Donald Trump should first be convicted by the Senate and then prevented from ever running for or holding public office again.

The proceedings will be jarring, not least because they will force us back into a traumatizing moment that was devastating to the story so many like to tell of American exceptionalism, of the relentless march of progress and democracy. They will remind us of a national nightmare that was all-consuming for so long but that now seems almost like a fever dream.

Trump has been out of office for less than three weeks, but in those three weeks Joe Biden and his team have worked to so thoroughly scrub the body politic of Trump’s toxic influence that it’s almost easy to forget just how vile and omnipresent the man was for the past four years. In the silence created by Trump’s banishment from social media, one can listen for the spring sounds of political rebirth—not that everything has suddenly been righted, but, for now at least, space has been created for rational political discourse in place of the bombast and sadism of the Trump era.

For those of us who were writing about Trumpism for those four long years, it’s been a relief, almost spiritual in its intensity, to not wake up every morning and ponder just how low the moral tone would sink that day, and just how destructive the political pronouncements would be.

There is, however, a danger in this rapid-onset amnesia. Both Trump himself and the political forces he either unleashed or accelerated were so atrocious that they will affect the American story—and the political allegiances of people on the left and the right—for decades to come. While it may be tempting to treat the Trump era as aberrational, as a one-off fluke, doing so risks smoothing the way for a redux version of the 45th president’s term. If we do not learn from this awful period and do not recognize just how close American democracy came to being destroyed in the final, desperate weeks of the Trump presidency, then at some point in the not too distant future we risk a return to demagoguery and the all-out assault on the truth that Trump orchestrated.

Which brings us back to the vastly important Senate impeachment trial: Trump’s lawyers have made it clear that they will argue two key points: (1) that Trump cannot be constitutionally tried, since he is no longer in office; and (2) that even if he can be tried, he can’t be convicted because, under the First Amendment, he had every right to use whatever inflammatory, dishonest language he wanted in front of his angry mob of supporters on January 6.

The first of these arguments has been so thoroughly debunked by constitutional law experts, from all sides of the political aisle—as well as defeated politically in a 55-45 Senate vote on the constitutionality of the trial—that it won’t pick up anywhere near enough traction to derail the proceedings. The second argument, while perhaps tenable on a debating platform, risks saddling the GOP with a toxic legacy for years to come. If Republicans hold to it, it will allow Democrats to label them as the party too in hock to a corrupt, brutal, and authoritarian leader and his acolytes to stand up to them even when his shouting-fire-in-a-crowded-theater words inspired a fascist mob to hunt down politicians it opposed, murder a Capitol police officer, and cause the death of several others.

The vast majority of Republican senators, unlike Trump’s more fanatical sycophants in the House, are unlikely to defend his January 6 words and actions—or, more generally, his increasingly bellicose and dangerous “stop the steal” campaign in the period between November 3 and January 6. Instead, they will try to obfuscate; to say that with Trump out of office—and out of sight—there is no need to hold such a trial; to claim that the proceedings are just political payback. Some, such as Lindsey Graham and Rand Paul, will likely build on recent statements in which they have played the party pragmatists, warning their colleagues that they risk splintering the party’s base if they vote to convict, and arguing that if Trump did indeed commit criminal acts, the courts rather than Congress should deal with him.

But the longer the trial goes on, and the more the House managers present the evidence of Trump’s lies, calumnies, and, ultimately, insurrectionary actions, the more unsustainable this head-in-the-sand position will become. This is, after all, a little bit like a turkey shoot: Trump’s actions were so malign, and so many of them were carried out in broad daylight, that now with Trump himself sidelined and lacking a social media podium from which to fully respond—and with his lawyers having nixed the idea of his testifying in person—Raskin’s team ought to have no problem detailing the full extent of the political cancer that metastasized into the lethal events of January 6.

Already some GOP senators, such as Lisa Murkowski, have dropped substantial hints that they are open to voting to convict if the evidence leads them to conclude that Trump is guilty of inciting an insurrection. Several others, including Mitt Romney, who voted to convict Trump after his first impeachment trial, will almost certainly join Murkowski as the evidence piles up.

A majority of the American voting public has since January 6 supported the Senate’s both convicting Trump and barring him from running for office again. As the evidence is put before senators and audiences around the country and the world, support for conviction will surely grow—perhaps not among die-hard Trumpist Republicans, but among the all-important political middle, the independents so coveted by both major parties. They already expressed their distaste for Trumpism at the ballot box in November; that distaste will not dissipate as images of Trump’s fanatical mob and his inflammatory speech to that mob saturate TVs, cell phones, and computers over the coming weeks.

This puts the GOP in a politically perilous position: Defend Trump’s actions—in which his mob tried to hunt down his own vice president in order to hang him—and the GOP ends up on the wrong side of the majority of voters; vote to convict him, as he so surely merits, and the GOP senators risk alienating their own primary voters, a large majority of whom remain stubbornly loyal to Trump.

The party that so opportunistically embraced Trump and Trumpism back in 2016 is now about to be hoist with its own petard. Damned if they do and damned if they don’t, the GOP senators are about to face a grand, and very public, reckoning over their Faustian bargain.