Donald Trump has declared war on reality. And reality is winning.

He campaigned as a self-anointed Emperor of Information, advancing his own — often false — version of the world. He’s doing the same thing as president, making patently untrue claims about voter fraud during the election and about crowd sizes during his inauguration.

Those falsehoods are largely harmless. They might feed his insatiable ego but don’t directly affect public policy or the national welfare.

But now his penchant for prevarication is getting serious, and two recent episodes demonstrate why: the downfall of National Security Adviser Mike Flynn and the determination of three federal courts to block his executive order on refugees.

In Flynn’s case, intelligence officers uncovered evidence that he was possibly breaking the law by talking to the Russian ambassador before Trump took office and assuring him that the new administration would take a softer line than its predecessor on economic sanctions against Moscow.

Dogged reporting by Washington Post columnist David Ignatius surfaced the story in mid-January, and Team Trump went into complete denial mode. A Trump spokesman told the Post that “economic sanctions were not discussed whatsoever” on the call. White House press secretary Sean Spicer told reporters that the call concerned only logistics: “That was it, plain and simple.”

Those were both falsehoods. Further reporting by the Post and The New York Times revealed that the acting attorney general, Sally Yates, had warned the White House about Flynn’s actual conversation weeks before. Hours after those stories appeared, Flynn resigned.

Trump reacted by blaming others, of course. “The real story here is why there are so many illegal leaks coming out of Washington?” he tweeted. And in a sense, he’s right.

The “real story” here is that reality is revolting against the president. Professional fact-finders refuse to be intimidated by the Emperor of Information.

To answer the president’s question: There are “so many illegal leaks coming out of Washington” because the Trump administration so often refuses to tell the truth.

The president’s executive order, barring refugees for 120 days and banning all travelers from seven Muslim-majority countries, also demonstrates his aversion to veracity. The president and his lawyers insisted that the order was essential to protect the nation’s security. But two district court judges, whose main job is fact-finding, disputed that assertion.

One of them, Leonie M. Brinkema, who sits in Virginia, said the president’s lawyers “have not offered any evidence to identify the national security concerns that allegedly prompted this EO (executive order).”

She then quoted approvingly from a statement by 10 former “national security professionals”: “We view the rder as one that ultimately undermines the national security of the United States, rather than making us safer.”

The president also maintained that the order had caused minimal disruption, but again Brinkema disagreed on the facts. Just one of many examples she cited in her opinion: In 2015, 465 foreign students from the seven banned countries enrolled in Virginia schools. Barring such students in the future would cost more than $20 million in lost tuition and fees.

Another argument advanced by the White House is that the order contained no direct reference to Muslims, and thus did not impose any discrimination based on religion. Again, Brinkema went to the record, citing statements by Trump during the campaign that he wanted “a total and complete shutdown of Muslims entering the United States.”

Those statements, said the judge, indicated his true intent, no matter what the order said. Finally, the judge rejected Trump’s assertion that federal law gives him unfettered power over immigration questions. “Maximum power does not mean absolute power,” she lectured.

The lesson from both cases is clear and compelling. Professional fact-finders — lawyers, judges, journalists, academics, researchers, scientists, intelligence officers — cannot be deterred or intimidated.

No matter how many tweets and tantrums emanate from the president, no matter how many “alternative facts” he presents, no matter how many leakers he denounces, the truth still matters. And we have to keep telling it.

Steve and Cokie Roberts can be contacted by email at stevecokie@gmail.com.