Logic — you know, reasoning based on strict principles of validity — has taken a beating over the course of the grotesquery known as the Trump presidency, but you have to really ignore reason to swallow the latest assault on logic emanating from the bowels of the White House as Trump fulminates over James Comey’s tell-all memoir: Deputy Attorney Rod Rosenstein can no longer oversee Robert Mueller’s Russia scandal probe because he was a big player in one of the president’s many bad acts under investigation by the special prosecutor.

Axing Rosenstein would be Trump’s predicate act prior to finally making good his oft-repeated rant that the special prosecutor must be fired because it logically follows that he is a Hillary Clinton stooge who is engineering a deep-state plot against the president. But to fire Mueller, inconveniently Trump probably must first get rid of Rosenstein, who supervises the special prosecutor’s increasingly deep and broad investigation into Russian interference in the 2016 election, the Trump campaign’s collusion in the cyber-espionage of Clinton and the president’s repeated attempts to shut down the whole megilla.

Getting rid of Rosenstein because he authored the letter articulating the reason Trump used to fire FBI Director Comey — that he was mean to Clinton during the campaign — does have a sort of comedic logic.

That is until one recalls that although Comey did treat Clinton unfairly in the course of the FBI’s off again-on again-off again investigation into her use of a private email server as secretary of state, in the process further crippling a campaign already being kneecapped by the Kremlin with the help of the Trumpsters and their Cambridge Analytica helpmates, the real reason Comey was fired was his fledgling Russia investigation, which was getting way too hot for Trump to handle. So he had to go.

Go Comey did, but in one of the more amazing episodes in this entire Dostoevsky-esque saga, it then fell to Rosenstein, a Trump appointee and lifelong Republican, to appoint a special prosecutor to sift through the wreckage of Comey’s efforts. That was Mueller, a Bush appointee and another lifelong Republican, who happened to be perhaps the only investigator with the chops to take down Trump. Which he is well on his way to doing.

The mastermind of the Get Rosenstein brainstorm is said to be Steve Bannon, Trump’s campaign and White House strategist, who departed the adult day care center known as the West Wing for a whirlwind Revenge on Mainstream Republicans Tour but like the proverbial bad penny, keeps coming around.

Bannon, according to The Washington Post, is also recommending the White House cease its cooperation with Mueller, reversing the policy of what’s left of Trump’s legal team to provide information to the special counsel’s crew and allow staff members to sit for interviews, which 20 or so already have done. And he’s telling the president that he needs to create a new legal battleground to protect himself from Mueller by asserting executive privilege and arguing that Mueller’s interviews with White House officials over the past year should now be null and void.

This is a not-so-clever iteration of the Dumb and Dumber Strategy first rolled out by Trump son-in-law Jared Kushner and later picked up by other Trumpkins when Mueller began turning up the heat: The campaign was too chaotic and incompetent to collude with those clever Ruskies.

Bannon’s view is that Trump’s lawyers are too incompetent to give him proper legal advice.

“The president wasn’t fully briefed by his lawyers on the implications” of not invoking executive privilege, Bannon told The WaPo. “It was a strategic mistake to turn over everything without due process, and executive privilege should be exerted immediately and retroactively.”

The timing for these turn of events does have a certain logic.

House Speaker Paul Ryan, who could never deliver for Trump (let alone the American people, whom he repeatedly tried to hoodwink) finally delivers in announcing that he’s fleeing the sinking Republican congressional ship.

Trump fixer Michael Cohen is now in a big fix himself as evidence mounts that there was a strategy to buy the silence of women and others by suppressing accounts of Trump’s infidelities that could have harmed his election chances, including the bomblet dropped on Thursday that the publisher of The National Enquirer not only paid former Playboy model Karen McDougal $150,000 for her “catch and kill” silence but coughed up $30,000 to a former doorman at a Trump building to prevent him from publicizing a (possibly false) rumor that Trump fathered a child out of wedlock.

Meanwhile, Mueller continues to turn up the heat, Trump’s former campaign manager is under indictment and faces spending the rest of his life in prison, his former national security adviser has pleaded guilty to lying to investigators about his own illegal activities, Kushner is in very deep legal doo-doo, and sundry other reprobates and grifters surrounding the president also are under scrutiny.

And most timely of all, Comey’s tell-all memoir on Trump, already a runaway pre-publication bestseller, hits doorsteps all over America on Tuesday.

Reviewers are portraying A Higher Loyalty: Truth, Lies and Leadership as a devastating takedown of Trump as a relentless liar and slave to his ego who is obsessively unethical, devoid of humanity, clueless about his job and unconcerned about Russia’s ongoing assault on American democracy.

The Republican National Committee has responded by launching a digital ad campaign and website that will brand the former FBI director as “Lyin’ Comey,” while Trump, in a pair of tweets on Friday, called him an “untruthful slime ball,” a “proven LEAKER & LIAR,” and said it was “my great honor to fire” him.

The activist group MoveOn claims more than 300,000 people have pledged to attend “rapid response” protests should Trump go “full Nixon” and fire Mueller, while it does seem like all he needs to do so is a wee nudge.

According to the West Wing leak machine, Trump is “nearing a meltdown” — or “Acting on Impulse,” as a scary WaPo headline put it — and telling friends and aides that he is willing to engage in political warfare to stop his presidency from being consumed by the Russia scandal investigation.

That, of course, is illogical, although you have to give the guy credit for having learned nothing from firing Mueller. Which Bannon, in an outbreak of truthiness, told “60 Minutes” was one of the worst mistakes in “modern political history.”

What is logical is that Trump’s presidency already has been consumed by the investigation and getting rid of Mueller will be like pouring gasoline on the conflagration.