During Barack Obama’s administration, the conservative author and activist Dinesh D’Souza wrote a book, “Obama’s America,” full of gross speculations about the sex life of the president’s mother, Stanley Ann Dunham, who was a pioneering anthropologist. “Ann’s sexual adventuring may seem a little surprising in view of the fact that she was a large woman who kept getting larger,” wrote D’Souza. He described her as a “playgirl” who used “her American background and economic and social power to purchase the romantic attention of third-world men.”

D’Souza’s insinuations had little to do with his ostensible thesis, which was that Obama sought to undermine America. It was simply a timeworn insult — calling someone’s mom fat and promiscuous — that tells us nothing about Obama’s family, but a lot about D’Souza’s character.

Besides being a huckster and a sexist weasel, D’Souza is a felon who, in 2014, pleaded guilty to routing illegal campaign donations through a woman he was having an affair with, and the woman’s husband. (At the time, D’Souza was married and serving as president of the evangelical King’s College. His ex-wife would later accuse him of physical abuse.) For his crime, he spent eight months in a halfway house. On Thursday, Donald Trump gave him a full pardon, tweeting that D’Souza had been “treated very unfairly by our government.”

Trump’s action, a clear abuse of his pardoning power for political ends, serves several purposes. Most seriously, the D’Souza pardon, like those of the former Arizona sheriff Joe Arpaio and the former Dick Cheney aide Scooter Libby, is a message to Trump confederates facing legal trouble. It says that if they stay strong, he’ll take care of them. As a former federal prosecutor, Joyce Alene, pointed out on Twitter, D’Souza was convicted of one of the same crimes, a campaign finance violation, that Trump’s lawyer Michael Cohen is now being investigated for.

The pardon is also a culture war smoke bomb, distracting from manifold other scandals and disasters: the study estimating that around 4,600 people died in Puerto Rico as a result of Hurricane Maria; outrage over migrant children ripped from their parents’ arms at the border; and an incipient trade war with our allies. Adding to the diversionary spectacle, on Thursday, Trump told reporters that he was considering commuting the sentence of former Gov. Rod Blagojevich of Illinois, a onetime contestant on Trump’s “Celebrity Apprentice,” and pardoning Martha Stewart, who hosted a “Celebrity Apprentice” spinoff.

D’Souza, who made his name in the 1990s fighting campus political correctness, once had a reputation as a middlebrow conservative provocateur, but he’s really more gutter-dwelling troll. His 1995 book “The End of Racism” argued, “In summary, the American slave was treated like property, which is to say, pretty well,” and called for the repeal of the Civil Rights Act of 1964. D’Souza wrote a bizarre book blaming the “cultural left” for provoking the jihadists who struck America on Sept. 11 and arguing for an alliance of the American right and conservative Muslims in “opposition to American social and cultural depravity.” During the Obama years he, like Trump, became a full-bore conspiracy theorist, accusing the president of spearheading a third-world scheme to subvert America.

In the Trump era, he’s become even worse. He mocked survivors of the Parkland, Fla., high school shooting who cried after the Florida Legislature voted down an assault weapons ban, tweeting, “Worst news since their parents told them to get summer jobs.” (He later apologized.) He described Rosa Parks as an “overrated” Democrat. He played a major role in spreading the lie — which Barr tweeted on Tuesday — that the billionaire financier George Soros, who was a Jewish child in Nazi-occupied Hungary, was really a Nazi collaborator.

And now Trump has singled this man out for grace. One former White House official, speaking to BuzzFeed News, denied that there was “any grand strategic reasoning” behind the pardon, which may well be true. But even if Trump was acting out of instinct rather than calculation, he has an intuitive ability to speak to his supporters’ dark impulses, and an insatiable need to smash boundaries that constrained his predecessors.

The fact that D’Souza is utterly undeserving of a pardon might be part of the point; it signals that fealty to the president transcends all other values. In his new book “The Road to Unfreedom,” the historian Timothy Snyder quotes the Russian fascist philosopher Ivan Ilyin, who is beloved by Putin’s circle. Fascism, Ilyin wrote approvingly, is “a redemptive excess of patriotic arbitrariness.” Trump has almost certainly never read this line, but he understands it.

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