Columnist

After Monday's legal shock and awe, one thing is certain: The Mueller investigation poses a serious and perhaps existential threat to the Trump administration.

Apologists for the president can yell "nothing burger" until they're blue in the face. Former Trump campaign chairman Paul Manafort and his associate Rick Gates — now under home confinement and charged with offenses that carry long prison terms — would likely disagree. Campaign adviser George Papadopoulos, whom special counsel Robert S. Mueller III has "flipped" into cooperating with the probe, also might attest that Monday's acts and revelations are a very big deal.

President Trump had good reason to spend that morning upstairs in the White House residence, brooding and fuming. Regarding Manafort and Gates, Trump perhaps could argue that Mueller has made no allegation — thus far — of collusion with the Russians to boost Trump's prospects in the election. But the Papadopoulos case, according to court documents, is all about Russian mischief — and what the Trump campaign may have known about it.

Perhaps the nastiest surprise for Trump and those close to him is that Papadopoulos, who was on the campaign's foreign policy team, was arrested July 27 and became a "proactive cooperator" with the Mueller probe. Papadopoulos pleaded guilty Oct. 5 to making false statements, in an interview with the FBI earlier this year, regarding his contacts with foreigners about obtaining Russian help for the campaign.

That is ominous news on every level. First, while there had been speculation that Mueller might go after Manafort and Gates, no one outside of Mueller's team appears to have known anything about Papadopoulos. How long has he been cooperating with the investigation? And what might that cooperation have entailed?

Anyone who had a conversation with Papadopoulos since his July arrest has to wonder whether he was wearing a wire. That's what a "proactive cooperator" often does. Gulp.

Equally unsettling for the White House is the fact that Mueller and his all-star squad of prosecutors managed to keep their engagement with Papadopoulos secret for so long. That took real discipline and sense of purpose. It also signals to Trump and his attorneys that they don't have anything close to a full picture of what Mueller is up to.

Have others connected with the Trump campaign been squeezed for information in a similar way? Is more proactive cooperating presently taking place? Speak clearly into my tie pin, please.

So what, exactly, did Papadopoulos do? He had a series of meetings with a London-based professor who has connections with the Russian government, and in an April 2016 encounter this professor claimed the Russians had "dirt" on Hillary Clinton that included "thousands of emails."

This was after Russian hackers had broken into the email system of the Democratic National Committee and also managed to steal the private emails of Clinton campaign chairman John Podesta. It is reasonable to assume that these are the emails that the professor was talking about to Papadopoulos, who made repeated attempts to set up meetings between the Trump campaign and Russian officials — even suggesting, at one point, a meeting between Trump and Vladimir Putin.

No such get-together took place. But in June 2016, there was that meeting at Trump Tower at which senior figures in the Trump campaign — Manafort, Donald Trump Jr., and Jared Kushner, Trump's son-in-law — met with a well-connected Russian lawyer in hopes of receiving "dirt" on Clinton.

Were the Russians exploring various avenues that might lead to a meaningful connection with the Trump campaign? Did they find one? As it happened, the DNC and Podesta emails were eventually released through WikiLeaks in a manner clearly designed to do maximum damage to the Clinton campaign.

We also know that the Russians flooded social media with pro-Trump fake news. In many instances, this propaganda campaign targeted voters at such a granular level that one has to wonder where the Russians got such sophisticated and detailed data. Mueller will be wondering the same thing.

Trump must have noticed that one important name was not prominently mentioned Monday: that of Michael Flynn, his short-lived national security adviser. Flynn faces potential legal jeopardy for his alleged representation of foreign interests without properly registering to do so. Trump has consistently gone out of his way to protect and defend Flynn, even to the point of asking then-FBI Director James B. Comey to go easy on him. Why such uncharacteristic compassion?

If I were Trump, I'd have to wonder if Flynn could be cooperating with Mueller. I'd worry about what he might say. And if I spoke with Flynn, I'd choose my words very carefully.

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