Rod Rosenstein's near-miss almost-exit from the Department of Justice on Monday should make clear an important fact: Special Counsel Robert Mueller's investigation of President Trump is now in a race against time.

It may already be too late to save the special counsel investigation. After all, Rosenstein will meet with President Trump on Thursday, and it's possible he'll leave the White House without a job.

If that happens, it means that the ultimate crisis of the Trump administration — which has seemingly been a series of fresh crises every news cycle — is finally at hand. We are about to find out whether the president or the rule of law has primacy in this country.

Things are bound to get ugly.

Why are we here? Because The New York Times reported on Friday that Rosenstein — never a favorite of Trump's — had discussed secretly recording Trump and even considered an attempt to oust the president using the 25th Amendment. Rosenstein denied the report, but the damage was clearly done.

The ramifications, of course, go far beyond Rosenstein's job status.

Rosenstein has been overseeing Mueller's investigation of possible collusion with Russia during the 2016 campaign, a responsibility he took on when Attorney General Jeff Sessions was forced to recuse himself from the matter. Nobody expects the attorney general to keep his job long after November's midterm elections. Trump would almost certainly expect the new AG to curtail Mueller's activities, if not bring them to a complete halt.

That has at least given Mueller some breathing room for his investigation, a clearly marked end date to work against. Rosenstein's exit would speed up the timeline.

In his absence, the overseeing of Mueller would likely fall to Solicitor General Noel Francisco, who has argued that the president has expansive power to fire executive branch employees if he chooses. Given that outlook — and President Trump's own clear preferences in the matter — it seems probable Francisco would, at the very least, hobble Mueller's probe.

That would be the turning point.

It should be astonishing that the president could and would order an end to the investigation of his activities. During normal times, that would be a signal to Congress to step forward and exercise its check-and-balance role on the White House, either through impeachment or some other method. The Republican-held House and Senate, however, have long since demonstrated their disinterest in restraining Trump.

Which means that if Mueller is sidelined, it will fall to voters in November — and whether they choose to replace those GOP majorities — to make the ultimate decision about Trump's fate.

There are those who will argue that Rosenstein's exit would amount to the Trump administration's version of the "Saturday Night Massacre," when Richard Nixon tried to undermine the Watergate investigation by firing a special prosecutor, only to cause the attorney general and deputy attorney general to resign.

But the truth is that the Trump administration has been All Massacre, All The Time since the Russia investigation began. The Department of Justice leadership has been undermined and decapitated by the president ever since — the firings of FBI Director James Comey and, later, Deputy FBI Director Andrew McCabe, the constant public belittling of Sessions, and his clear contempt for Rosenstein have brought us to this moment. We don't yet know if Trump's attempt to restock the DOJ with loyalists has had its desired effect, but the intent is nonetheless clear.

If there's reason for hope in all of this, it's that Trump — by so nakedly acting in his own service instead of the country's — has made heroes and sympathetic figures of men who might otherwise be poorly judged by history. Comey, after all, helped swing the election to Trump with his ill-considered comments about Hillary Clinton in the waning days of the 2016 campaign; Rosenstein wrote the tendentious memo that Trump used to justify firing Comey. Sessions, if not for his role in the Russia matter, would be remembered as a chief architect of Trump's brutal immigration policies.

But all three men have held the line against Trump's efforts to meddle in the Russia investigation — and each has paid a price for doing so. In this era where we're inclined to see our political rivals as our enemies, it's helpful to look upon Comey, Sessions, and Rosenstein and see that they're human: They may not always do their jobs well, or they may have awful political ideas, but they do seem to have demonstrated moral integrity in the face of pressure. That's something to be admired, isn't it?

If so, let's hope we're not admiring martyrs to the rise of Trump. Instead, we should want the possible end of Rosenstein's Justice Department career to mark the moment when the rule of law reasserted itself against the designs of small, selfish men.

Either way, it looks like the endgame is finally afoot.