President Trump raged at his TV on Sunday morning. And yet on balance, he had a pretty good weekend. He got a measure of revenge upon the hated FBI, firing former Deputy Director Andrew McCabe two days before his pension vested. He successfully coerced his balky attorney general, Jeff Sessions, into speeding up the FBI’s processes to enable the firing before McCabe’s retirement date.

Beyond this vindictive fun for the president, he achieved something politically important. The Trump administration is offering a not very convincing story about the McCabe firing. It is insisting that the decision was taken internally by the Department of Justice, and that the president’s repeated and emphatic demands—public and private—had nothing whatsoever to do with it.

Pay no attention to this, from July 26, 2017:

December 23, 2017.

Or this, from December 24.

Or uncounted more.

As former CIA Director Michael Hayden observed, under military justice, these interventions by the president would have required the dismissal of charges against an accused on grounds of undue command interference.

But in the hours since the McCabe firing, Trump’s enablers in Congress and in conservative media have evinced no such concern. They have accepted the story that McCabe was honestly investigated and independently disciplined without qualm or quibble. In the words of former Fox News anchor Brit Hume:

“It’s certainly conceivable that Trump, being Trump, would reach into the inner workings of the FBI and Justice Dept. to frame Andrew McCabe and get him fired. But anyone who claims that’s what happened needs to provide evidence to back it up. Mere supposition doesn’t cut it.”

But aren’t the president’s own written and globally published demands for a firing some kind of evidence?

Apparently not.

All this matters even more urgently when you consider the McCabe firing as a road test for Trump’s method in an impending showdown with Special Counsel Robert Mueller.

What will the president’s party in Congress permit? What will the president’s media supporters repeat? What will the president’s supporters in the country believe? The story they have been told about McCabe previews the story they will soon hear about Mueller.

As many have noted, Trump’s March 17 tweet about Mueller—his first to attack Mueller by name—heaps lie upon lie.

The allegations did not originate with the Steele dossier; many of the dossier’s claims have been corroborated; the FISA court behaved properly; and there has been enough evidence of crime to lead to the indictment of Trump’s former campaign chairman, Trump’s former national-security adviser, and 13 Russian nationals.

But the test for Trump is not credibility or even plausibility. It is the reliability of his party, his media, and his voters. The McCabe practice test yielded answers that have to be gratifying for the president as he ponders his next move to save himself, his family, and his administration from the workings of justice.