If special counsel Robert Mueller finds that Donald Trump colluded with Russia to fix the 2016 election, or even if Mr. Trump fires Mr. Mueller before he makes such a finding, Mr. Trump's supporters will protect him from any political fallout.
Mr. Trump's base will stand by him not because they believe Mr. Trump is on their side, but because they define themselves as being on his side.
Mr. Trump has intentionally cleaved America into two warring camps: pro-Trump and anti-Trump. And he has convinced the pro-Trumps that his enemy is their enemy.
Most Americans are not passionate conservatives or liberals, Republicans or Democrats. But they have become impassioned Trump supporters or Trump haters.
Polls say about 38 percent of Americans approve of him, and most disapprove. These numbers are the tips of two vast icebergs of intensity.
Mr. Trump has forced all of us to take sides, and to despise those on the other. There's no middle ground.
The Republican Party used to stand for fiscal responsibility, state's rights, free trade and a hard line against Russian aggression. Now it just stands for Mr. Trump.
Pro-Trump Republicans remain the majority in the GOP. As long as Mr. Trump can keep them riled up, and as long as Republicans remain in control of at least one chamber of Congress, he's safe.
"Try to impeach him, just try it," Roger Stone, Mr. Trump's former campaign adviser, warned last summer. "You will have a spasm of violence in this country, an insurrection like you've never seen."
That's probably an exaggeration, but Mr. Trump (with the assistance of his enablers in Congress) has convinced his followers that the Russian investigation is part of a giant conspiracy to unseat him, and that his enemies want to replace him with someone who will allow dangerous forces to overrun America.
Sure, this paranoia is based on the same racism and xenophobia that has smoldered in America since the nation's inception. Mr. Trump's strategy is to stoke it daily.
Sure, American politics had polarized before Mr. Trump. Mr. Trump's strategy is to exploit and enlarge these divisions.
A few months ago I traveled to Kentucky and talked with a number of Trump supporters.
They looked and sounded nothing like traditional conservative Republicans. Most were working class. Several were members of labor unions. All were passionate about Mr. Trump.
"Why do you support him?" I asked.
"He's shaking up Washington," was the typical response.
I mentioned his lies. "He's telling it like it is," several told me. "He speaks his mind."
I talked about his attacks on democracy. "Every other politician is on the take," they said. "He isn't. He doesn't need their money."
I asked about the Trump campaign's possible collusion with Russia. They told me they didn't believe a word of it. "It's a plot to get rid of him."
By making himself the center of an intensifying conflict, Mr. Trump grabs all the attention and fuels even greater passions on both sides.
It's what he did in the 2016 election, but on a far larger scale. Then, he sucked all the oxygen out of the race by making himself its biggest story. Now, he's sucking all the oxygen out of America by making himself our national obsession.
Mr. Trump received more coverage in the 2016 election than any presidential candidate in American history. Hillary Clinton got far less, and what she got was almost all about her emails.
Schooled in reality television and New York tabloids, Mr. Trump knows how to keep both sides stirred up: Vilify, disparage, denounce, defame and accuse the other side of conspiring against America. Do it continuously. Dominate every news cycle.
Fox News is his propaganda arm, magnifying his tweets, rallies and lies. The rest of the media also play into Mr. Trump's strategy by making him the defining controversy of America. Every particular dispute -- DACA, the "wall," North Korea, Mr. Mueller's investigation and so on -- becomes another aspect of the larger national war over Mr. Trump.
It's the divide-and-conquer strategy of a tyrant.
Democracies require sufficient social trust that citizens regard the views of those they disagree with as worthy of equal consideration to their own. That way, they'll accept political outcomes they dislike.
Mr. Trump's divide-and-conquer strategy is to destroy that trust.
So if Mr. Mueller finds that Mr. Trump colluded with Russia, or Mr. Trump fires Mr. Mueller before Mr. Mueller makes such a finding, the pro-Trumps will block any consequential challenge to his authority.
Nothing could be more dangerous to our democracy and society.
Robert Reich, a former U.S. Secretary of Labor, is professor of public policy at the University of California at Berkeley. Robert Reich's new book, "The Common Good," is out Feb. 20. His documentary, "Saving Capitalism," is available on Netflix.