“We’ve never had a president who trades in conspiracy theories, who prefers lies instead of fact,” Douglas Brinkley, a history professor at Rice University and a presidential historian, told me.

Read: Trump is surrounded

A U.S. president has at his disposal the most authoritative information available on Earth. Yet Trump doesn’t seem to want it. Disdainful of credentialed professionals, Trump has taken extraordinary steps, and spent taxpayer dollars, standing up dubious ideas of his own creation.

In September, with Hurricane Dorian bearing down, Trump clung stubbornly to his claim that the storm’s path put Alabama in jeopardy. The reason isn’t entirely clear, but he may have wanted to come across as the savior of a loyal red state that turns out in force for his rallies. After a local office of the National Weather Service corrected him, the White House intervened, culminating in an official administration statement rebuking a scientific agency that had dared challenge the president’s bogus forecast.

Claiming that millions of people voted illegally in the 2016 election and cost him the popular vote, Trump set up a White House commission to see if there was widespread voter fraud—a nonexistent problem requiring no solution. It disbanded last year without turning up any evidence that Trump was robbed of a popular-vote victory. He also accused Obama's FBI of trying to surveil his campaign from the inside, but the Justice Department inspector general is expected to debunk that claim in an upcoming report.

The Ukraine debacle is the most extreme case, illustrating just what can happen when the president takes hold of a bad idea and won’t let it go. Repellent to Trump is the notion that he would have lost to Hillary Clinton had it not been for Russia’s electoral interference. The self-image he’s constructed rests on the idea that he’s rich and successful—not a “loser,” the epithet he routinely hurls at opponents. Trump has worried that if people believe Russia’s interference spelled the difference in the election, it could undermine his legitimacy, Special Counsel Robert Mueller’s report showed.

All of which explains why, for the president, the Ukraine fiction is so alluring. It’s a twofer. If Ukraine covertly interfered in the election for Clinton’s benefit, as Trump has suggested, that would both exonerate Russia and cement his 2016 victory. Trump apparently finds that theory so compelling that he risked his presidency to see if he could give it traction. Loyal appointees are now pushing his message: In a news conference on Tuesday, Secretary of State Mike Pompeo said that Ukraine merited investigation. The United States has “not only a right, but a duty” to look into any “information that any country has messed with American elections,” Pompeo said.

Trouble is, none of this has a basis in reality. Members of Trump’s own staff and intelligence-community officials have all debunked the idea that the culprit was Ukraine, not Russia.