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Donald Trump will never really go away, even if he is resoundingly defeated on Tuesday. Not on November 4, not on January 20, not when he dies, not in a hundred years. He may well be what future generations remember most about our era. Not because of what he accomplished, but because the story of a mad king is an immortal tale.

The phenomenon is rare, which is why it is so captivating. The Roman emperor Caligula appointed his horse a consul of Rome. He made it illegal for anyone to look at him in the street, was an enthusiastic sadist, and seems to have genuinely believed that he was a deity. King George III of England, whose madness would be made into a Hollywood movie, supposedly tried to shake hands with a tree, thinking it was the King of Prussia, although this story was almost surely apocryphal. America has been relatively immune to this sort of leader, although Richard Nixon had some moments in his final, besieged years—ordering military operations he never intended to carry out, musing openly about using the Army to hold on to power, and pouring out vitriol on tape.

The mad king also makes for great literature. Game of Thrones begins a few years after the death of one such figure and introduces its share of irrational leaders along the way. William Shakespeare’s King Lear is the story of a monarch who responds well to flattery and is taken advantage of by his own daughters.

Trump is not trying to shake hands with a tree, but he does have many of the features, weaknesses, and idiosyncrasies of the stereotype. The president is incapable of empathy, susceptible to flattery, and prone to self-destructive behavior. He has a mercurial family that exerts undue influence over his administration. He traffics in the most absurd conspiracy theories. His wealth, or lack thereof, is shrouded in secrecy. He is insecure. He lays out his deepest prejudices on Twitter for the world to see. He captivates crowds. Everything about him—the hair, the tan, the long tie, the goofy hat—is outlandish.

He is the president of one of the most powerful countries in history, one that invests unrivaled authority in its commander in chief, including the right to use nuclear weapons. He also has formidable adversaries with powerful stories of their own—the first African American president and the person who would have been the first female president. And it looks like he could meet his political end partly because of a plague. It’s hard to get more biblical than that.

What will make the Trump story particularly irresistible for future generations is that it’s not just a comic farce; it’s also of huge significance to anyone who wants to understand the United States in the early 21st century.

Ever since Trump was elected, political theorists have debated whether his presidency is a cause or a symptom of political change. The conventional wisdom is that he is a symptom of a bigger shift. He benefited from trends that were already under way—the disillusionment of non-college-educated white voters, the shock waves from the financial crisis, and distrust in authority. All of this is true, but that argument overlooks the effect that the president’s irrational behavior has had on America.

If, say, Ted Cruz had been elected president in 2016, he too would have benefited from populist trends. Many commentators would have asked if Cruz’s nationalism spelled the end of the liberal international order—after all, he was the first candidate in the 2016 election cycle to use the term America First to describe his foreign policy. The Europeans would have almost certainly been distraught about his election. But a Cruz presidency would have been qualitatively different from Trump’s. He would surely not have played doctor during the pandemic, actively promoting unproven medicines or advising the public to inject themselves with disinfectant. He would not have tweeted orders at the Pentagon. He would have likely shown empathy when he met a Nobel Prize winner whose six brothers and mother were murdered by the Islamic State. He would not have proclaimed his love for Kim Jong Un.

The Cruz hypothetical is helpful in understanding what about this time historians might attribute to Trump, in particular. To the extent that they focus on certain aspects of his administration’s policy—voter suppression, tax cuts for the wealthy, his failure to stand up for democracy abroad, and the ramming through of a Supreme Court justice while voting is under way—Trump is a symptom, not a cause of change. He may even be less radical than others who might follow him, including Cruz.

However, Trump’s ineptitude and erratic behavior also shaped the trajectory of the country. He seemed incapable of reading a brief and of having foresight that extended beyond tomorrow. He had no desire to actually do the job of president and was vindictive toward civil servants who were doing theirs, meaning that much of the government was hollowed out under his watch. He did not feel a responsibility to citizens of states that did not vote for him. And now we are seeing just how irrationally he would act in a crisis, even when his actions hurt his own political interests. He refused to treat the coronavirus as a real risk, and now the country is in its third wave of infections and has suffered more than 19 percent of the world’s fatalities, even though it makes up only 4 percent of the global population.

Voting Trump out of office will probably not decouple the Republican Party from Trumpism. But it could strike a decisive blow against the notion that entrusting the presidency to someone who is so obviously unfit for the role is acceptable. And that is not nothing.

Future historians might conclude that in the end, American democracy was strong enough to survive Trump—that is, if the election takes place without disruption. If Trump wins, then all bets are off. He will feel utterly vindicated and will believe that he alone represents the will of the people. It is a short step from that level of hubris to an attempt to fundamentally remake and even undo key elements of American democracy and the country’s global role.

Trump is now an intrinsic part of the story of America—its first mad president. The only major question left is whether the story relayed decades and even centuries from now will end with what Trump did to America or with what America did to Trump. That will be answered soon.

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