President Trump walks across the South Lawn of the White House on Friday. (Alex Brandon)
Opinion writer

The White House is taking yet another big step to declare any and all oversight conducted by the House of Representatives fundamentally illegitimate, placing President Trump above accountability entirely. The New York Times reports:

President Trump is preparing to instruct his former White House counsel, Donald F. McGahn II, to defy a congressional subpoena and skip a hearing scheduled for Tuesday, denying Democrats testimony from one of the most important eyewitnesses to Mr. Trump’s attempts to obstruct the Russia investigation, a person briefed on the matter said on Monday.

The House Judiciary Committee has subpoenaed Mr. McGahn to appear. The White House plans to provide Mr. McGahn, who left the post last year, with a legal opinion from the Justice Department to justify his defying the subpoena, the person said.

McGahn was the star witness to many of the most serious obstruction of justice efforts by Trump detailed in special counsel Robert S. Mueller III’s report. Democrats want to flesh out these accounts with the help of McGahn himself, something that is plainly within Congress’s authority.

It’s odd that Trump World’s position continues to be that Mueller’s report totally exonerated Trump, but also that we must not hear from anyone who helped produce that totally exonerating account ever again. But put that aside. Can the White House keep McGahn from testifying?

As Politico reports, the Justice Department is preparing a legal opinion justifying the move on executive privilege grounds. It’s true, as Politico notes, that the long-standing position of presidential administrations in both parties, including that of President Barack Obama, has been that close presidential advisers have “absolute immunity” to congressional subpoenas, to preserve presidential prerogatives.

But in this case, the legal theory is being used as part of a much broader across-the-board strategy of maximal resistance to oversight on all conceivable fronts. Trump himself has openly confirmed this, vowing to fight “all” subpoenas, and we’ve also seen it applied in the administration’s effort to keep Trump’s tax returns secret.

Still, as Eric Columbus, who served as a lawyer in the Obama administration, points out, McGahn is a former employee of the White House, which means that if he wants to testify to Congress, he can.

But Trump has an answer to this problem, as the Times further reports:

If Mr. McGahn ... defies the White House, Mr. McGahn could not only damage his own career in Republican politics but also put his law firm, Jones Day, at risk of having the president urge his allies to withhold their business. The firm’s Washington practice is closely affiliated with the party.

That’s pretty remarkable: It is being discussed as a realistic possibility that Trump would threaten to destroy both McGahn’s career and the business prospects of his law firm if he honors a legitimate congressional subpoena designed to get to the bottom of an extraordinary accounting of corruption and wrongdoing produced by a legitimate law enforcement investigation.

That this was noted almost as a banal, unremarkable factor, observed with barely a raised Timesian eyebrow, is itself an indication of how low we’ve sunk here.

In this regard, the case of Rep. Justin Amash (R-Mich.) is instructive. Over the weekend, Amash became the first Republican to declare that Mueller documented impeachable offenses by Trump. This was greeted with a furious diatribe from Trump himself, and even a primary challenger, who insisted that Amash is “out of touch” with both “the truth" and “the people he represents," which is to say, Amash has broken with the alternate reality of this whole affair that Trump and his propaganda machine have created in the minds of countless of his voters.

Republican lawmakers will be watching Amash closely, to gauge what fate befalls those who dare to deviate from the sacred principle that impunity and freedom from accountability for Trump must be prioritized above all else. Similarly, if McGahn does defy Trump’s demand and testifies before Congress, many members of the GOP establishment will be closely watching to see what sort of professional price he pays.

Of course, if McGahn is cowed into doing Trump’s bidding, and refuses to testify, that bodes very badly for the rest of us.

If that happens, by the way, this battle will go to the courts, and this might paradoxically further strengthen the case for Democrats launching an impeachment inquiry. As I’ve noted, an inquiry could strengthen the legal hand of Democrats in forcing cooperation with their oversight demands. Politico recently spelled out how court rulings buttress this argument.

Indeed, Michael Conway, who served as a House lawyer during Watergate, told me that the McGahn example is a particularly stark case. As it is, Conway noted, the case for exerting executive privilege over McGahn’s testimony is particularly weak, because McGahn has already testified on these matters at great length to Mueller. Adding an impeachment inquiry would make it even weaker.

“Congress has issued a valid subpoena," Conway told me. “And courts have said that when Congress is doing oversight, its power to enforce a subpoena is not as strong as when it’s doing an impeachment inquiry.”

On top of this, the ludicrousness of the executive privilege claim itself could help build the political case for impeachment. Conway pointed out that one component of one article of President Richard M. Nixon’s impeachment was a similar “improper use of executive privilege,” exercised to prevent a congressional investigation of Nixon’s wrongdoing, just as is happening now.

Of course, if Democrats have privately determined to never pull that trigger no matter what, this could all be moot. And if, at the same time, McGahn doesn’t testify out of fear of Trumpian retaliation, Trump’s lawlessness will continue to expand into the vacuum created by Democratic inaction.

Read more:

Jennifer Rubin: Why Justin Amash stands alone

The Post’s View: Could this be ... a Republican with backbone?

Max Boot: The GOP doesn’t have to impeach Trump. But it also doesn’t have to nominate him.