Those public statements created a situation where firing Sessions would create a backlash from Republican senators and a huge media scandal, since Trump himself had all but said it would be for the purpose of obstructing justice.
It was July 2017, sixteen months ago, when Trump told the New York Times that if he had known Sessions would recuse himself from the Russia investigation he never never would have hired him.
But it was that very statement that made it so much harder to do what what he wanted and fire Sessions. So months passed while Mueller was diligently working away — amassing evidence, turning witnesses and handing down indictments — and Trump could fire Sessions only after the midterms were over.
Then when he finally did it, Trump once again acted without any subtlety or understanding of how his moves would be interpreted publicly, installing Matthew Whitaker as acting attorney general likely in no small part because of Whitaker's apparent hostility to the Mueller investigation.
But Whitaker became so controversial so quickly that it's now impossible for him to fulfill Trump's wishes without, once again, causing a huge media scandal. Whitaker now seems to feel that his hands are tied on this matter; the AP reports that "Whitaker told Republican Sen. Lindsey Graham in a meeting on Thursday that special counsel Robert Mueller's investigation will proceed."
And now, Republicans in the Senate are pushing the administration to find a new attorney general who can be confirmed quickly — which means someone who will pledge in their confirmation hearings not to interfere in the Mueller investigation:
Even after Trump's latest attack on Mueller in a flurry of tweets Thursday, most Republicans argue the president will not fire Mueller or derail his investigation because the political consequences would be too great.
But they said that naming an attorney general nominee as soon as possible — specifically one who would vow to preserve the Russia probe — would go a long way in halting legislative momentum to protect Mueller and Democratic messaging that acting attorney general Matt Whitaker will undermine the investigation.
"If we had some confidence that there is somebody nominated that would be confirmed in a reasonable period of time, to me it seems like it would relieve a lot of the controversy," said Senate Majority Whip John Cornyn of Texas, who predicted that Whitaker, who was openly critical of the Mueller probe before Trump tapped him for the job, is "not going to be there long."
Meanwhile, all indications are that after a long period of silence during the close of the midterm campaign, Mueller is about to do something big, or a series of somethings.
Trump's former factotum Michael Cohen was spotted Monday coming to Washington with one of his criminal defense lawyers.
Paul Manafort has held multiple meetings in recent weeks with Mueller's team. On Wednesday, Mueller asked the court to delay sentencing for former Trump aide Rick Gates, saying Gates "continues to cooperate with respect to several ongoing investigations." Trump's orbit is reportedly gripped by anxiety about what's coming.
When Trump lashes out on Twitter in increasingly hysterical terms as he did Thursday, it might (as many have speculated) suggest that he knows something bad is coming his way.
But his anger comes from impotence. If he knew he was about to get his way with Mueller, he wouldn't be shouting about it on Twitter. It's the fact that he can't do anything about it that fills him with rage.
We don't know how many more Trump aides will wind up serving time behind bars, what Mueller's final conclusions will be or how much the president himself will be implicated in the scandal.
What we do know is that Trump wanted to stop the investigation, and not only has he failed, he has made everything worse for himself.