Devin Nunes (R-Calif.), the chair of the House Intelligence Committee, is an exception to the rule that committee chairs, male or female, are allowed to run things as they choose. Democrats, left-wing groups, and those who obsess about Trump won’t let him.

Were Democrats in charge, Nunes would probably be their Target No. 1. His sin was switching the committee’s focus from collusion between the Trump campaign and Russian operatives in the 2016 presidential election to finding out why the Trump campaign was being investigated in the first place.

Nunes would like to know why one volunteer adviser to Trump, Carter Page, was wiretapped for a year and another minor aide was sought out by an FBI informant. And a fair question is whether these cases were less a search for evidence of Trump-Russia collusion than a covert way of looking inside the Trump campaign—illegally.

In any case, Democrats are still furious at the committee’s change of direction, though it occurred more than a year ago. They’d like to deep-six the investigation entirely. At one time or another, they’ve called for Nunes to step down as chairman or resign from Congress or just clear out of town.

Since Nunes refuses to back down, Democrats and their allies have been waging a war of abuse, slander, and name-calling. They’ve tried with occasional success to make his life miserable. Nunes has to be protected by a security detail when he leaves his office.

The mainstream press is no less unfriendly. Even the Fresno Bee, his hometown paper, has been harshly critical of Nunes, referring to him as “Trump’s stooge.” It relies on the favorite claims by Democrats to poison the public’s view of what Nunes is doing.

“He certainly isn’t representing his Central Valley constituents or Californians, who care much more about health care, jobs, and, yes, protecting Dreamers than about the latest conspiracy theory,” the paper wrote in January. “Instead, he’s doing dirty work for House Republican leaders trying to protect President Donald Trump in the Russia investigation.”

With that, the Bee was just warming up. Nunes aims “to discredit the FBI and distract the public.” And he is pursuing this “at the same time special counsel Robert Mueller’s probe appears to be picking up steam and focusing on possible obstruction of justice by the president.”

When Nunes put out a memo with preliminary findings last winter, Democrats went crazy. It raised questions about the legitimacy of the “Steele dossier,” the collection of negative (but unverified) information about Trump that was put together by former British spy Christopher Steele. It was submitted to the Foreign Intelligence Surveillance Court to justify the wiretapping of Carter Page.

The submission was a deceptive document. It masked the fact that the Democratic National Committee and Hillary Clinton’s presidential campaign had paid for the dossier—the tab was $168,000—making it a partisan document. This was improper as grounds for a wiretap of an American citizen, a blatant one.

When the Nunes memo was released, House minority leader Nancy Pelosi was joined by Chuck Schumer, the Senate Democratic leader, in freaking out. The memo said the Steele dossier was the key document cited to justify the wiretap of Page.

But what was Schumer doing there? He has enough trouble in the Senate. Did he make a wrong turn in the Capitol? No. The dossier matter was just getting too hot for Democrats. House speaker Paul Ryan backed Nunes, as he has consistently.

And it got hotter when the actual FISA application was released in mid-July, revealing just how much had depended on the hearsay collected by Steele. Nunes and his memo were vindicated.

The mainstream press disagreed, but they’re obsessed with driving Trump out of office. Giving credit to Nunes for uncovering alarming holes in the FBI probe and exposing the pro-Democratic tilt of its investigation might help Trump. Can’t have that.

Vindication won’t spare Nunes harassment by the left. This is what those folks do in their spare time. And complaints to the House Ethics Committee against Nunes are piling up. Three left-wing groups accused Nunes of making classified information public last year, causing him to step down as leader of the investigation for eight months while the ethics committee dawdled before ruling in his favor.

Meanwhile, responses to his tweets pour in. It turns out the anti-Nunes forces are far from witty and a good number of them think he ought to be in prison. Nunes isn’t fazed by dumb tweets or mean charges.

Last week he tweeted this when CNN asked him for a comment: “ ‘CNN’s slavish adherence to the Democrats’ comical talking points is an amazing sight to behold.’ . . . Guess what? They refused to run the statement. . . . This is another great example of ‘Fake and fraudulent news.’ ”

It wasn’t easy to pick the best response. The quality was so low. But here it is: “It would be helpful if DN had talking points that were made in America not Russia.”

But here’s why we should be grateful to Nunes and wise members of the intelligence committee like Chris Stewart from Salt Lake City. We wouldn’t know these things if they hadn’t dug them up. (1) Hillary and the DNC paid for the still-unverified Steele dossier from his Russian sources. (2) The Steele dossier was largely responsible for approval of the Page wiretap. Well worth knowing, don’t you think?