Possible collusion between Russia and the Trump campaign was once little more than a conspiracy theory, but not anymore. The only way to make sense of this week’s stunning events is to conclude that there is something that President Trump desperately wants to hide.

The party-line explanation of why Trump fired FBI Director James B. Comey — that it was all about the way Comey handled the probe of Hillary Clinton’s emails — crumbled within hours. Press secretary Sean Spicer comically ducked behind shrubbery on the White House grounds, hiding from television cameras, to give reporters a confused and disjointed account of the dismissal. Efforts to blame the whole thing on Deputy Attorney General Rod J. Rosenstein ceased after Rosenstein reportedly threatened to resign.

Well-sourced reports in The Post, the New York Times, the Wall Street Journal and other news outlets agreed on a very different explanation: Trump had grown increasingly angry at the doggedness with which Comey’s FBI was investigating how and why Russia meddled in the election. The president decided to fire Comey, then had Attorney General Jeff Sessions and Rosenstein come up with a rationale.

If this were a criminal trial, prosecutors would allege that the president was displaying “consciousness of guilt” — that he was acting in a way no innocent person would act. Indeed, the only other president to try to head off an investigation by firing the chief investigator was Richard Nixon.

Of course, Trump is not accused of anything at this point. And it may be just a coincidence that on Wednesday, a day after firing Comey, the president met in the Oval Office with Russian Foreign Minister Sergei Lavrov and Russian Ambassador Sergey Kislyak. Photographers from the White House press corps were barred from the meeting, but one who works for the Russian news agency Tass was allowed in. Perhaps Trump only thinks of U.S. journalists as “the enemy.”

(Adriana Usero/The Washington Post)

I do believe in mere coincidences, up to a point. And I know that conspiracy theories usually turn out to be wrong. But I can see no explanation for Trump’s bizarre attitude toward the allegations of Russian meddling other than a desire to conceal something.

For months, Trump dismissed the conclusion of the U.S. intelligence community that Russia was ultimately responsible for hacking into computer systems and email accounts associated with the Democratic Party, then leaking information that was damaging to Clinton’s campaign.

Trump named Michael Flynn — a controversial figure, partly because of his ties to Russian President Vladimir Putin — as his national security adviser. And when Sally Yates, then serving as acting attorney general, told the White House that Flynn had lied when he denied discussing U.S. sanctions with Kislyak, and thus could be vulnerable to Russian blackmail, Trump waited 18 days to fire him. The president acted only after Flynn’s deception became public knowledge.

And Flynn had been a prominent Trump adviser during the campaign. Experts say he might be in legal jeopardy, which makes him someone an aggressive investigator such as Comey would likely squeeze for information about others.

During the campaign, Sessions, who was then a U.S. senator, and Trump foreign policy adviser Carter Page also met with Kislyak — as did Trump’s son-in-law, Jared Kushner. It is possible that these were nothing more than courtesy calls. But given the backdrop of a Russian effort to boost Trump’s prospects of winning the election, all meetings between senior campaign figures and Russian officials deserve scrutiny.

In an interview Thursday with NBC’s Lester Holt, Trump said that Comey told him once over dinner and twice in phone calls that he was not personally being investigated. Trump described one of the exchanges this way: “I said, ‘If it’s possible, would you let me know, am I under investigation?’ He said, ‘You are not under investigation.’ ”

Trump apparently thinks this means something, but of course it does not. Typical investigative procedure is to start at the bottom of an organization and work your way up. “You are not under investigation” does not mean “you will never be under investigation.”

Trump claims to have no business ties with Russia. But in the past, his sons have reportedly bragged about a flood of Russian money boosting the Trump Organization’s fortunes. Trump could settle the question by fully disclosing his finances, including his tax returns. Why the secrecy?

If Trump wanted to end this scrutiny by firing Comey, he may have had the opposite effect. Ask yourself one question: Have you ever seen a coverup with no underlying crime? Neither have I.

Read more from Eugene Robinson’s archive, follow him on Twitter or subscribe to his updates on Facebook. You can also join him Tuesdays at 1 p.m. for a live Q&A.