In the nearly four years that Donald Trump has been president, he has obliterated many things we used to think were true.
One of them was the illusion most Americans once held that our system has guardrails, carefully erected by the Founders of this country to protect it from the urges of demagogues and tyrants.
When a narcissistic reality-TV star was elected to the presidency in 2016, it was still possible to believe that the enormity of the office itself would force anyone who holds it to grow and change.
It was imaginable that under the weight of having to make decisions upon which Americans' lives were literally on the line, he would come to appreciate the value of relying on science and expertise and experience.
And that there were institutions of government, such as the Justice Department and the courts, that could put a check on his impulses.
And that there were some lines -- say, squeezing a foreign government to investigate a domestic political opponent -- that not even Trump would cross.
And that ours was not the kind of government that would rip migrant children from their parents without any means of reuniting them.
There surely would come a point, it seemed reasonable to think, when the wiser heads of Trump's own party, if for no other reason than self-preservation, would demand a change in a reckless course that threatened to take them all over a cliff.
Instead, Republicans marched in lockstep behind him, fearing the lash of his Twitter feed. They lost the House in 2018 and possibly will sacrifice their Senate majority on Tuesday.
Four years ago, Americans -- not a plurality of U.S. citizens, but enough of them who live in key electoral states -- saw in Trump an experiment worth trying. He was an outsider, a businessman, someone who gave voice to their own frustrations with a political system that left them behind and a culture that mocked their values.
At the same time, many discounted his divisive rhetoric and outlandish ideas like building a wall on the border. As journalist Salena Zito memorably put it, they took him seriously, not literally, while the media took him literally, not seriously.
It turns out Trump should have been taken both seriously and literally. He has exhausted all but his most loyal base with his nonstop lying, his racism and xenophobia, his sexism, his crazy conspiracy theories, his grifting, his incompetence.
What is different as Trump runs in 2020 is that the country has seen and experienced who he really is. A second Trump term would be no different than his first, except that it would be worse.
In an election that Trump appears to be on track to lose, he seems uninterested in expanding his appeal beyond the 45% or thereabouts of Americans who support him. He doesn't consider himself answerable for the suffering in cities and states that did not vote for him.
So one by one, segments of the electorate that gave him the benefit of the doubt in 2016 are peeling away from him.
Voters older than 65, normally a Republican constituency and one that Trump won easily, now appear to be leaning toward former Vice President Joe Biden, the Democratic nominee. It is probably no coincidence that these are the citizens most vulnerable to the coronavirus and a pandemic that, thanks in some measure to Trump's mishandling, has cost more than 228,000 Americans their lives. But Republicans began losing older voters even before covid-19 hit.
The economy was thought to be Trump's main selling point, especially among college-educated white men, a cohort he narrowly won in 2016. Polls show a majority of them now support Biden. The president has alienated women to the point where this election is likely to produce a gender gap of historic proportions. Nor is Trump running as strongly as he did four years ago among whites without college degrees, who are considered the core of his base.
None of which is to say it isn't possible the president might still win on Tuesday, or whenever it is that the votes are finally counted. But a country that would give him a second chance would be one that is vastly different from the one that elected him in 2016.
Biden is right when he says that "four more years of Donald Trump will fundamentally change the nature of who we are as a nation." Reelecting him would be a conscious choice to do exactly that.
That is the difference this time around. America no longer has any illusions about who Trump is. What remains to be seen is what it believes itself to be.