When President Biden snapped at a reporter, “Don’t make things up” over the weekend, I couldn’t help but recall all the “facts” he had imagined into being in an effort to scare up support for gun control — a dialogue that has hurt prospects for making our nation safer. 

If Mr. Biden wishes to reduce gun deaths, the only place to start is with honest debate. Instead, he offers his own “facts,” and this only makes a solution more elusive as gun homicides hit record highs on his watch.

Many politicians lie — about sex, about crimes, about their son’s laptops — tossing out strategic untruths of the means-justify-the-ends variety, but Mr. Biden is no Machiavelli. Playing loose with the truth on guns serves no purpose on the chessboard, resulting only in the president shooting himself in the foot.

Take his declarations that the Second Amendment didn’t permit civilians to own cannons when it was ratified. What is gained by repeating that falsehood again and again?

What’s accomplished when Mr. Biden claimed a 9mm bullet “blows the lung out of the body”? It sounds like something out of a Looney Tunes short and renders our leader an unserious buffoon.

It would be one thing if the president discarded what are charitably called “misstatements” after they’re exposed. This is, after all, the Walk Back White House. Yet he keeps repeating the falsehoods even after being called on them — for example, thundering that Americans can buy whatever they want at gun shows, “no background check.”

In fact, federally licensed firearm dealers — which account for 78 percent of sales, according to a 2015 survey cited by FactCheck.org — must still examine purchasers regardless of the venue.

It sounds great, too, when the president says that “red flag laws” have reduced suicides, but there’s no evidence to back it up, with a RAND examination finding any correlation to be “inconclusive.”

Another presidential favorite — that gun manufacturers are “exempt” from liability unlike any other corporation — cites the bipartisan Protection of Lawful Commerce in Arms Act of 2005. While that law does indeed provide protections from frivolous lawsuits and hostile governments seeking to infringe on constitutional rights, gunmakers can indeed be sued.

Just last February, Remington settled with parents of the Sandy Hook massacre for $73 million, and any of their competitors can likewise be sued if their products fail to function as designed.

As for being unique, other corporations enjoy similar protections. Major League Baseball is exempt from antitrust law, as are other major sports to varying degrees, and Big Tech can’t be held liable for user content. Plus, thanks to the 2005 Public Readiness and Emergency Preparedness Act, Pfizer and Moderna enjoy complete immunity from liability if you are harmed by vaccine side-effects.

An NBC News headline called out another favorite bit of rhetoric: “President Biden Claims More Kids Are Dying from Guns Than Cars. That’s Not the Whole Story.” The figures hold up “only when 18- to 19-year-olds,” meaning adults, not kids, “are included, a group that accounts for nearly as many gun deaths as 1- to 17-year-olds combined do.”

These aren’t just harmless flubs. They libel honest gun owners, make the job of those seeking to get weapons off the streets harder, and misinform the American voter on the nature of the crisis. 

Meanwhile, each time fact-checkers must call out the president, they spill ink that might otherwise be spent on a discussion of the Second Amendment’s “well-regulated militia” and the limits possible for “the right to keep and bear arms.”

Every one of these falsehoods agitates legal gun owners and saps energy from Mr. Biden’s allies, a neat trick of forcing both sides of the debate to go on defense. All the while, the problem festers and Americans lose interest in the bickering — until the next shooting, the next candlelight vigil, the next hashtag, the next empty political posturing.

Mr. Biden has made a brand of shooting off his mouth when he has a goal he wishes to achieve, but on the life-and-death matter of guns, he’d do better to take his own advice: “Don’t make things up.”