And then they came for Robert Mueller.

If there were any remaining hope that Republicans would accept the precise, methodical work of this veteran, highly respected, Republican-appointed law enforcement official — the man Newt Gingrich once called a “superb choice to be special counsel” — it has evaporated in a fog of propaganda and delirious conspiracy theories.

In the real world, Mr. Mueller, appointed as special counsel after President Trump fired the F.B.I. director, James Comey, in May, is doing the job he was hired to do — smoke out any and all links between the Trump campaign and the Russian government officials who assaulted American sovereignty in 2016 in an effort to get Mr. Trump elected. These days, the most serious attacks on American governance are coming not from abroad, but from Mr. Trump’s aides and his allies in the right-wing media and Congress. As ludicrous as these attacks seem, they could yet lead to a constitutional crisis.

Reading the increasingly outlandish theories cooked up by Mr. Trump’s defenders and apologists is like entering an alternate, upside-down universe where Hillary Clinton remains Public Enemy No. 1.

In these irrelevant tales, Mrs. Clinton (or, as Sean Hannity called her on Monday, “President Clinton”) is the real colluder, working stealthily with the Russians to — stay with us here — destroy her own candidacy. Also, she and Bill Clinton once sold American uranium to the Russians. Also, Robert Mueller failed to fully investigate that sale when he led the F.B.I., so he’s complicit in it, too, not to mention he has ties to Mr. Comey, who also led the F.B.I. Also, some of his investigators donated to Democratic candidates.