In substantial measure, Donald J. Trump owes both his celebrity status and accidental presidency to his impulsiveness, his willingness to say whatever he's thinking without considering the long-term consequences. Of course, the qualities that make a successful reality television star are not what make a successful president. The Trump impeachable offense du jour is the nearly inevitable result of a classic example of shortsightedness: Trump's snap decision to fire FBI Director James Comey.

On Tuesday, Michael Schmidt at The New York Times uncovered the existence of a memo written by Comey summarizing his meeting with Trump on Feb. 14. According to Comey's notes, Trump suggested that the FBI should give a pass to Michael Flynn, Trump's initial choice for national security adviser who had been fired the previous day because he had been compromised by ties to the Russian state. "I hope you can let this go," Trump allegedly said to Comey.

Trump's decision to fire Comey alone provided powerful circumstantial evidence of Trump obstructing justice. Trump's initial justification for the firing — that Comey had mishandled the investigation into Hillary Clinton's email server, over which Trump had repeatedly called for Clinton to be imprisoned — was a comically obvious pretext. Indeed, the explanation was so specious that before the end of the week, Trump had conceded to NBC's Lester Holt that he fired Comey for refusing to rapidly conclude the FBI's investigations into Russia's attempts to intervene in the 2016 elections on behalf of Trump.

Tuesday's revelations, however, take all this to a new level. Trump apparently pressured Comey to stop investigating a prominent administration official. This is exactly the kind of obstruction of justice that forced Nixon to resign.

And things are likely to get worse for Trump before they get better. It's hard to believe at this point that Flynn isn't guilty of serious wrongdoing, given the lengths Trump — who has never had the slightest qualm about burning former associates who are no longer useful to him — has gone to protect him. And we now know that Comey took meticulous notes about every meeting with Trump. At this point it would be shocking if these notes didn't contain further examples of gross misconduct by Trump.

Trump's impulsive firing of Comey, in other words, is proving to be disastrous for his interests. Comey — who for better or worse is strongly committed to his view of himself as independent and above partisan favor — has every incentive to make sure that his side of the story gets out there. Tuesday's story makes it likely that Comey will be testifying in front of Congress soon. And the content of the rest of the non-classified memos are likely to be made public as well.

Needless to say, Democrats immediately called for the Comey memos to be released. To show how serious the scandal is, however, House Oversight Committee Jason Chaffetz is also planning to subpeona all documents relating to the Comey/Trump meetings. That even Chaffetz — who all but declared he would be Trump's poodle after conducting two years of Hillary Clinton snipe hunts — feels compelled to investigate Trump, or to at least create the appearance of investigating Trump, shows what political danger the Republicans are in.

One possibility going forward is that the Republicans decide to cut their losses, remove Trump from office either by impeachment or, on 25th Amendment grounds, get rid of a president who is likely to be an anvil for Republicans in the 2018 midterms.

At this point, however, Chaffetz — who isn't running in 2018 — remains the exception rather than the rule. Republican legislators continue to limit themselves to vague assertions of being "troubled." And there's a reason for this: Republicans have created a monster. While Trump's never-good approval ratings are tumbling among the population as a whole, he remains very popular with the Republican base: According to a Quinnipiac poll, 84 percent of Republican voters think Trump's first 100 days in office have been a success. Unless he becomes much less popular with Republican voters, acting to remove Trump would tear the party apart. And this is unlikely to happen — historically partisanship has been surprisingly resilient to even the biggest scandals, and defections have generally come from the kind of moderates who are virtually extinct in today's GOP.

Politically, then, Republicans have no good options for dealing with a president who is grossly unfit for office. And James Comey, whose actions may well have put Trump in the White House, might also be responsible for the political implosion of his presidency.