A weird syllogism attends to the Russia investigation today, one that is now being ardently pushed by President Trump's defenders. It holds that because the crimes that Trump may have committed are insuperable from the decisions a president may legally make — akin to decisions that a CEO makes about personnel choices inside her company — if there is at least a plausible reason beyond criminality that the president might have made a choice, he must be given the benefit of the doubt. A crime is not committed unless, this weird theory goes, the House impeaches and the Senate convicts based on a bill of charges that they themselves write. That is, the crime becomes a crime only after the accused has been charged with a crime. Before — and in the absence of a congressional trial — the president can do whatever he wants.

This theory is as unsettling as it is dubious, but a weak, compliant Congress, and the lack of a full accounting from Special Counsel Robert Mueller, might mean that, by the time this chapter in history closes, the president will have established the right to immunize himself and future presidents from scrutiny.

But short of Trump firing Mueller, we will get a full accounting from the special counsel. And it will be full.

You can get a flavor of what we might expect from Mueller in looking at the FBI's recent arrest of former Defense Intelligence Agency civilian case officer Ron Hansen on charges that he spied for China. The bill of particulars is factual and it goes into great detail, point by point, charge by charge. It is a public accounting of an alleged spy's poor tradecraft and it reminds us, once again, that it is really, really hard to hide anything from federal investigators.

On Aug. 9, 1974, a day after President Richard Nixon resigned, special prosecutor Leon Jaworski read a short memorandum prepared by two associates, Carl Feldbaum and Peter Kreindler, making a compelling case that Nixon could be prosecuted for the crimes he committed while in office. Two paragraphs from that memo are worth reproducing in full, as they bear directly on the public patter that Rudy Giuliani and President Trump have used to contour public opinion against the very idea that such a prosecution would ever be possible. (The italics are my own in both cases.)

1. The principle of equal justice under law requires that every person, no matter what his past position or office, answer to the criminal justice system for his past offenses. This is a particularly weighty factor if Mr. Nixon's aides and associates, who acted upon his orders and what they conceived to be his interests, are to be prosecuted for the same offenses.

2. The country will be further divided by Mr. Nixon unless there is a final disposition of charges of criminality outstanding against him so as to forestall the belief that he was driven from his office by erosion of his political base. This final disposition may be necessary to preserve the integrity of the criminal justice system and the legislative process, which together marshalled the substantial evidence of Mr. Nixon's guilt. [Carl Feldbaum and Peter Kreindler]

The media environment is different by orders of magnitude today. But the best thing Mueller can do, if it is true that he cannot or will not indict a president who he believes committed real crimes, is to let the facts captivate for themselves.

The Republican base is shrinking in its size but is more ardent in its support for the preservation of the president's power. And without the full accounting that we will one day get, the choice for Republican officeholders who want to preserve their own power is fairly easy. In public, they try not to comment on the president.

To their supporters, they selectively message issues that coincide with those that Trump promotes. They have maximized the umbrage and negative partisanship that can be held against the Democrats, just as the Democratic candidates are overmarinating themselves in Trump hatred. Privately, these Republicans tell their donors that they believe they can effectively contain Trump's populist economic instincts and they tell themselves that they will read Mueller's final words with keen interest.

At some point, possibly before the midterm elections, Mueller will lay out a case against the president. If he's got the goods, then it will be stark and damning. If he does not, it will be dull. (I suspect that, if he has nothing to say, he will say nothing.) But if there is a bill of particulars laid out for all to see, it could well serve as an alternative to spinal replacement therapy for Republicans who require non-Trump voters to win in November and beyond. And then, the calculus about impeachment changes.