Hollywood’s summer is more than halfway over, and the box-office report is telling: If you want to have a hit, don’t lard your film with tendentious, off-putting, off-topic political messages.

The summer’s big winners at the box office are mostly mindless spectacle: “Iron Man 3,” “Fast 6,” “Man of Steel,” plus cute family fare like “Monsters University” and “Despicable Me 2” and the buddy comedy “The Heat.” What they all have in common is that they pretty much lack any hint of a political argument.

That won’t stop Hollywood from trying to sneak, or rather ram, PC messages into its movies, but for the most part the ones that try are doing badly, notably “White House Down,” “The Lone Ranger” and “The Purge.”

“The Purge” is a low-budget movie that was spun as a hit, but the audience obviously hated it. It made about one-quarter of its total gross on its opening night, when it appeared to be a stupid horror thriller, but plummeted once word of mouth got around that it was instead a stupid political allegory.

In the movie, it’s 2022, and the New Founders rule the country. Though they’ve eliminated unemployment, they also have decreed that on one night each year, murder is legal, and the patriotic hooligans head out into the night wearing, in some cases, Sarah Palin masks. Director James DeMonaco has admitted that the New Founders are meant to make us think of the Tea Party and the NRA. Conservative writer Ed Morrissey said the message was as “subtle as a jackhammer welded to the grill of a Mack truck speeding at the viewers at 95 miles an hour.”

Audiences essentially replied: We were only interested in it for the crazy violence. If you’re going to make us think, forget it.

In “White House Down,” a Tea Party-like cabal goes so far as to attack the White House and force a president (Jamie Foxx) obviously modeled on Barack Obama into fighting for his life (right at the moment when he was going to sign a major peace deal and also eliminate poverty). The film is so overtly (and, given that its director is Roland Emmerich, comically) political that audiences couldn’t even take it as seriously as the generic “Die Hard” rip-off “Olympus Has Fallen.”

Said Isaac Chotiner of The New Republic, the film “resembles a season of ‘24’ as re-written by Noam Chomsky.” Hey, nothing says blockbuster like Noam Chomsky. “White House Down” is one of the year’s biggest flops.

Disney’s “The Lone Ranger” is meant to continue in the 50-year-history of “revisionist Westerns,” meaning “this time white dudes are the villains.” The title character is played as an oafish sidekick by the bland actor Armie Hammer, while the actual star is Johnny Depp as Tonto. Tonto informs us solemnly, “Indians are like coyotes. They kill and leave nothing to waste. What does the white man kill for?”

Simple. As Woody Allen once said, we kill for food. And not only that, frequently there must be a beverage.

But the tired idea that Indians were ecologists, right down to their allegedly noble killing habits, is itself an early-’70s myth that doesn’t stand up to historical scrutiny, so this would-be daring film gets stuck in PC quicksand.

In fact, the Indians used any wasteful methods they could to kill buffalo (including driving them off cliffs or setting fire to the land on all four sides), then left most of the meat to rot in the sun.

The villains of “The Lone Ranger”? Greedy capitalists. Like the ones at Disney who charge 3-year-olds $89 for a day’s admission to the Magic Kingdom.

I personally prefer politically alert movies because I find ideas (even wrongheaded ones) more interesting than car chases and explosions, but then again if I ran a studio I’d probably bankrupt it. I’m bored by movies like “World War Z,” which was widely expected to tank before its release but instead has done surprisingly well. Brad Pitt told Entertainment Weekly the much-discussed mid-production rewrites came about after the original idea was “a more political film, using the zombie trope as a kind of Trojan horse for asking, ‘What would happen to sociopolitical lines if there was a pandemic like this? Who would be on top? Who would be the powerful countries and who would be the most vulnerable?’ ”

Oh dear: This movie was going to be so bad, it actually had Brad Pitt saying “trope.” Instead, “WWZ” wound up being pretty much your standard shoot-’em-before-they-eat-you monster movie, only on a global scale.

The politics, Pitt added, was “too much to explain. It gutted the fun of what these films are meant to be.”

Every summer the Brad Pitts of the world have to relearn the wisdom of MGM mogul Sam Goldwyn (though the line attributed to him actually came from playwright Moss Hart): If you want to send a message, use Western Union.

kyle.smith@nypost.com