Nearly four years after his inauguration, Donald Trump is still frustrated every time he gets another lesson in the limitations of presidential power.

And with Election Day now barely three weeks away, that frustration, along with his continuing battle with Covid-19, has him flailing about, targeting not just his political opponents, but his own Cabinet.

Trump rebuked Attorney General Bill Barr and other cabinet officers on Thursday for failing to prosecute his political enemies — including Joe Biden and Barack Obama — for what he called “the greatest political crime in the history of our country.”

That “crime”? The FBI’s investigation into his 2016 campaign’s links to Russian meddling in that year’s election, largely on Trump’s behalf.

U.S. Attorney John Durham of Connecticut is conducting what amounts to a counter-investigation, looking into the FBI’s 2016 actions. But Barr says the Durham probe won’t be completed by Election Day, suggesting it has found little or nothing so far.

Barr has privately expressed his own unhappiness with Trump’s public commentary and criticism, although there seems little chance that he’ll be fired.

“Still, the tensions between Trump and the attorney general over the fate of the (Durham) probe underscore the extent to which the president is aggressively trying to use all of the levers of his power to gain ground in an election that has been moving away from him,” says the Associated Press.

The president, who is still in recovery from Covid-19 infection and receiving a steroid medication that could alter his mood, hasn’t been seen in person since returning to the White House on Monday, but he did do phone interviews with Fox News and Fox Business, along with a video directed at older voters — and the inevitable blizzard of Twitter posts.

Even for him, they were scattershot performances, ones that advisers said reflected increasing frustration over his political fortunes,” reported the New York Times.

Trump admitted he has pressured Barr to indict Obama and Biden without waiting for more evidence: “He’s got all the information he needs,” the president said.

Trump claimed that if Biden is elected, his presidency wouldn’t last “two months” because “he’s not mentally capable.” And that would put Kamala Harris — whom he called “a communist” — in the Oval Office.

He described FBI Director Christopher Wray as “disappointing” and said he’s “not happy” with Secretary of State Mike Pompeo for not releasing Hillary Clinton’s emails. Yes, those emails, central to a long-dead non-scandal that hangs about, zombie-like, on the fringes of American politics.

He even reposted Twitter messages contending that House Speaker Nancy Pelosi may be planning a “coup” against him, 23 days before the election.

And while Trump aims all this vitriol at his own top officials, some Republicans in Congress are refusing to go anywhere near him, fearing another Covid-19 “superspreader” event like the gathering last month to announce Judge Amy Coney Barrett’s nomination to the Supreme Court.

Sen. Mitch McConnell (R-KY), the majority leader, “indicated that he was boycotting the White House because of its lax handling of the virus,” the Times says.

“I haven’t actually been to the White House since August the 6th because my impression was that their approach to how to handle this is different from mine … which is to wear a mask and practice social distancing,” McConnell told reporters.