Among his talents, Donald Trump has a special gift for driving his detractors so crazy that they do really stupid stuff. The decision by Democrats to force Robert Mueller to testify before Congress is Exhibit A.

Bumblin’ Bob was a train wreck of epic proportions. The fallout is immediate, starting with this: Impeachment is no longer an option.

It had a slim chance before Wednesday’s painful slog and no chance after it.

Mueller was that bad, seemingly hard of hearing, often confused, and contradicted himself several times.

The Dems’ fantasy of having him breathe life into his report backfired.

His dismal performance killed any possibility that his 450-page tome could serve as a road map for overturning the 2016 election and driving Trump from office.

Although Mueller’s general demeanor was disturbing, it was also instructive. He did not project the mental and physical vigor of someone capable of leading the complex two-year probe into Russian meddling, possible Trump collusion and obstruction of justice.

More likely, the 74-year old former FBI director was something of a figurehead for an investigation that was carried out by the team of zealots he ­assembled.

That is not an incidental issue. As Andy McCarthy at National Review has written, and as Trump has repeatedly charged, the prosecutors were ­primarily people who had donated to Hillary Clinton and other Democrats or who otherwise made known their support for her.

Perhaps Mueller’s detachment explains his failure to remedy these obvious conflicts of interest that undercut his credibility from the moment they became known.

Oddly, Mueller removed FBI agent Peter Strzok because his bias against Trump became public, but apparently had no concerns about public reports showing that chief prosecutor Andrew ­Weissman and others were in Clinton’s camp.

Mueller’s detachment may also explain the bizarre standard his team created, where Trump’s presumption of innocence was shredded because they could not find sufficient evidence to “exonerate” him. Several Republicans pointed out that prosecutors either file charges or don’t, but have never imposed the impossible standard of exoneration.

Those flaws are among many that undercut the report, including the fact that much of it reads as if it were written by Trump-hating reporters from the New York Times.

As one GOP member noted, the report cites nearly 200 articles and broadcasts, giving the impression that the media set the probers’ agenda. At the very least, Mueller’s team and the media were joined at the hip from the get-go.

Because of its pro-Clinton bias, the probe was the evil twin of the initial FBI investigation it inherited. Recall that the crooked James Comey relied heavily on the infamous Steele dossier, which Clinton’s team funded.

So from start to finish, Trump was targeted by partisan law enforcement officials who had no business being on the case. And yet, despite a probe that ran a combined three years, involved hundreds of witnesses, thousands of subpoenas and surveillance on Trump associates and maybe the president himself, investigators could find nothing — nothing! — worthy of a criminal charge.

That can only help the president in his re-election campaign. While there is a long way to go, the cloud of possible impeachment, which existed since Mueller was appointed, finally has been lifted.

There are two other major developments growing out of the hearing.

First, House Speaker Nancy Pelosi now has the responsibility to get her party back to its job of governing. She gave the impeachment caucus and its fanatical leaders, Reps. Jerry ­Nadler and Adam Schiff, time to gin up public support, but they have gotten nowhere because the facts were not as they promised.

If Pelosi is as smart and practical as her supporters say, she will make it clear that the hearing was the end of the Mueller era. If, on the other hand, she hesitates and lets the wing nuts chase their fantasies, she will recklessly waste the next year and increase the chances the GOP will retake the House in 2020.

The other development is that Washington’s focus now shifts to the two investigations into the investigators. The first to drop will be the review of the surveillance warrants obtained against Carter Page, which is being carried out by the inspector general in the Justice Department.

The chief questions center on what Comey and others told the secret court’s judges about the Steele dossier. Did they disclose that it was paid for by Democrats?

Did they concede that Steele said he was motivated to make sure Trump did not become president? And did the judges know the allegations were unverified before granting four warrants?

The ultimate probe, though, is the one Attorney General Bill Barr launched. He said he was appalled at FBI bias against Trump and that he wants to get his hands around the origins and scope of the initial scrutiny.

“The use of foreign-intelligence capabilities and counterintelligence capabilities against an American political campaign to me is unprecedented and it’s a serious red line that’s been crossed,” Barr told CBS in May.

He also warned of the dangers of weaponizing law enforcement against political opponents, saying “the idea of resisting a democratically elected president and basically throwing everything at him” is a real threat to our nation.

There is no known deadline for Barr’s report, but my guess is that he will work relatively fast, certainly faster than the special counsel. And because Mueller’s day in the spotlight turned out to be a dud, Barr’s findings have the potential to be the real bombshell.