Evan Vucci/AP) (Evan Vucci/AP)
Opinion writer

In the past day or so, President Trump and the White House have instructed a former official not to comply with a House subpoena as part of an investigation into the dubious handling of security clearances. They’ve launched an unusual lawsuit to block House Democrats from accessing his finances. And they’re preparing to refuse to turn over his tax returns, which will likely violate the law.

Plainly, Trump is determined to treat any and all oversight as illegitimate — even though this is a core institutional function of Congress — with the goal of keeping his seemingly bottomless corruption shielded from public view.

But his power to do this is not limitless. And this constraint is making Trump very, very angry.

Democrats have now subpoenaed former White House counsel Donald McGahn to appear before Congress and testify about his direct involvement in some of the most explosive revelations in special counsel Robert S. Mueller III’s report.

Trump’s allies, led by Trump’s lawyer Rudy Giuliani, have ramped up their attacks on McGahn. The New York Times reports that they are escalating for a very specific reason: because they fear that McGahn will help build the case for Trump’s impeachment.

As the Times reports, some White House officials believe the attacks on McGahn are counterproductive. But the most important White House official of all sees things quite differently:

Mr. Giuliani’s attacks on Mr. McGahn have unnerved some senior White House officials, who have argued privately that the president and his legal team should stop drawing attention to damaging episodes in the report, according to two people close to the White House.

But Mr. Trump has privately complained about the accounts, particularly the ones given by Mr. McGahn, and has said the only way to protect himself from impeachment is to attack Mr. Mueller and Mr. McGahn, the people said.

Why would Trump fear such a thing, if the Mueller report totally exonerated Trump? Because Mueller’s recounting of episodes involving McGahn are profoundly damning, and highlight Trump’s corruption, bottomless capacity for official deception and contempt for our democracy and the rule of law with great vividness.

McGahn’s testimony was devastating

As Mueller documents, McGahn testified that Trump tried to instruct him to carry out one of his most glaring efforts to obstruct justice — and then to lie to cover it up. After the Times reported that Trump had ordered McGahn to fire Mueller, and then backed down when McGahn threatened to quit, Trump dismissed the story as “fake news.”

Trump then tried to get McGahn to deny this had happened — and even tried to get McGahn to put that in writing. But McGahn refused, claiming the story was accurate.

As Mueller recounts, Trump then demanded this in a face-to-face meeting with McGahn, claiming: “You need to correct this. You’re the White House counsel.” As always, here Trump seemingly treated McGahn as his personal lawyer, not the White House’s institutional one.

In a particularly revealing passage, Mueller recounts that Trump repeatedly told McGahn that despite any recollections otherwise, he never ordered Mueller’s firing. As the report puts it: “McGahn thought the President was testing his mettle to see how committed McGahn was to what happened." In other words, Trump was probing how much he could get away with in pushing McGahn to lie for him.

And then the Mueller report ties it all up in a neat little bow:

The President then asked, “What about these notes? Why do you take notes? Lawyers don’t take notes. I never had a lawyer who took notes." McGahn responded that he keeps notes because he is a “real lawyer” and explained that notes create a record and are not a bad thing. The President said, “I’ve had a lot of great lawyers, like Roy Cohn. He did not take notes."

Hopefully, McGahn will soon testify to all this — and much, much more — on live television.

Trump is in a rage again

Trump just raged at Times columnist Paul Krugman, claiming he’s “obsessed with hatred,” presumably because of Krugman’s latest claims, that Trump “welcomed” Russian sabotage of our election and tried to obstruct a full accounting of that sabotage, which Krugman said “betrayed the country.”

But it is simply true that Trump welcomed that sabotage, regardless of whether his campaign criminally conspired with it. And as I’ve argued, by obstructing the investigation, Trump was trying to impede a legitimate law enforcement inquiry not just into his own corrupt conduct — which itself is bad enough — but also to impede a full reckoning of that outside attack on our political system.

We know Trump wanted the truth about that attack to disappear, because he felt it diminished the greatness of his victory, which ended up hamstringing the government’s efforts to prepare for more interference to come.

All of this adds to a strong case for launching an impeachment inquiry, but Democrats are locked in an internal debate over whether to initiate one. They have settled on an uneasy compromise, in which they will ramp up investigations on numerous fronts with the goal of fleshing out the Mueller report’s conclusions, which could end up laying the groundwork for such an inquiry, though that’s hardly guaranteed.

At a CNN town hall on Monday night, Sen. Elizabeth Warren (D-Mass.) put all these pieces together, and showed why resisting such an inquiry will likely grow harder for Democrats:

We don’t know whether Democrats will finally launch an impeachment inquiry. But, with Trump throwing up so many roadblocks to legitimate scrutiny and oversight on so many fronts, they will simply have to use every tool at their disposal to expose as much of Trump’s corruption and misconduct as possible — and, equally important, to dramatize it before the American people.

Trump’s worry at the possibility of McGahn dramatizing his obstructive conduct is a key tell — an indication that Democrats do have such tools at their disposal, and that if they use them properly, there’s no telling where all this could lead.

Read more:

Jennifer Rubin: McGahn’s testimony should rock Trumpland

Eugene Robinson: Democrats must seize and define this moment. Otherwise, Trump will.

Adam Schiff: Congress must ensure that Trump is working for the American people — not foreign interests

Dana Milbank: Mueller’s findings: Too stupid to conspire. Too incompetent to obstruct.

Michael Gerson: House leaders should lay the groundwork for impeachment

Max Boot: My former party’s reaction to the Mueller report fills me with disgust