It had the makings of a Cold War whodunit: The attorney general tells the White House that the Russians have “kompromat” on the president’s national security adviser — but the president, for reasons unclear, stands by the compromised official.

On the morning of Jan. 26, acting attorney general Sally Yates called White House counsel Don McGahn with a matter so sensitive it couldn’t be discussed by phone. They met that afternoon at the White House, and Yates, accompanied by the top career official in the Justice Department’s national security division, dropped a bomb: President Trump’s national security adviser, Michael Flynn, had lied to Vice President Pence about Flynn’s contacts with Russia. This had left Flynn vulnerable to Russian blackmail, the Justice Department officials said — and Yates, an Obama administration holdover, said she was sharing the information so the White House could take action.

But McGahn had an odd response. He called the DOJ officials back to the White House the next day and asked them a perplexing question, Yates recounted to a Senate Judiciary subcommittee Monday afternoon: Why does it matter to DOJ if one White House official lies to another White House official?

Yates explained what should have been self-evident: Not only were Pence and the American public entitled to know the truth, but the Russians also knew that Flynn had lied to the vice president — so the Russians had the goods on him. “To state the obvious, you don’t want your national security adviser compromised with the Russians,” Yates testified. “Logic would tell you that you don’t want the national security adviser to be in a position where the Russians have leverage over him.”

But Trump didn’t move to fire Flynn. He fired Yates instead.

At the White House counsel’s request, Yates had arranged for him to see the evidence against Flynn on Monday, Jan. 30. But he didn’t come that day, and that night Yates was sacked for refusing to implement Trump’s order banning travelers from several majority-Muslim nations.

Flynn remained on the job, sitting in on highly classified sessions including a phone call between Trump and Russian President Vladimir Putin. Had The Washington Post not broken the story on Feb. 9 about Flynn’s contacts with Russia, he might still be on the job today. Trump reluctantly pushed out Flynn on Feb. 13 while insisting he’d done nothing wrong.

Three months later, Trump is still blaming Yates, not his mendacious former aide. “Ask Sally Yates, under oath, if she knows how classified information got into the newspapers soon after she explained it to W.H. Council,” he tweeted Monday, before correcting the spelling of “counsel.” (Republicans on the panel dutifully asked her, and former national intelligence director James Clapper, whether they had anything to do with such leaks; they said they did not.)

Where there is smoke there is not necessarily fire. But there is so much smoke from the Trump-Russia probe that you can’t get near it without a respirator. Monday’s hearing further pumped the bellows.

Clapper qualified his earlier statement that he knew of no collusion between the Trump campaign and Russia — a point House Intelligence Committee Chairman Devin Nunes has used to exculpate Trump. Clapper acknowledged Monday that he was “not aware of the counterintelligence investigation” the FBI was conducting on the matter.

Clapper rebutted the Trump argument that Obama officials (particularly Susan Rice, who declined to appear Monday) had improperly “unmasked” Flynn or others. Clapper said he was not “aware of any instance” of unmasking being used for political purposes.

Clapper confirmed, as well, that British intelligence and other European allies passed information to the United States in late 2015 and early 2016 about Trump campaign ties to Russia.

What’s known publicly about those ties is damning enough that the Trump response has been less a head-on refutation than complaints about the way the information came out — through “unmasking,” leaking or imagined wiretapping of the Trump campaign.

Though some Republicans on the panel engaged in such diversions — Ted Cruz raised the Anthony Weiner affair — the subcommittee chairman, Lindsey Graham, rose above partisanship. “When a foreign power interferes in our election, it doesn’t matter who they targeted,” he said. “We’re all in the same boat.”

The Trump White House, alas, takes a different view.

Yates, a career prosecutor until Barack Obama tapped her to be the No. 2 at the Justice Department, recalled the questions the White House counsel had about Flynn: Why did DOJ care? Would DOJ pursue a criminal case? Wouldn’t taking action against Flynn interfere with an investigation? And could he see the evidence?

After those skeptical questions, Trump took no visible action against Flynn until a public outcry forced him to. You don’t have to be Tom Clancy to wonder why.

Twitter: @Milbank

Read more from Dana Milbank’s archive, follow him on Twitter or subscribe to his updates on Facebook.