Senate Democrats claim to fear that Brett Kavanaugh will be too willing to overturn Supreme Court precedents, but it turns out that not all precedents are created equal. They’re also complaining that Judge Kavanaugh might fail to overturn at least one precedent—the landmark 2008 Heller decision upholding an individual’s right to bear arms.

Gun control is a favorite issue of California Senator Dianne Feinstein, who challenged Judge Kavanaugh at Wednesday’s confirmation hearing for following the Supreme Court’s Heller precedent too literally for her political tastes. The 2008 Supreme Court ruling struck down a Washington, D.C., ban on handguns. The district then banned so-called assault weapons including semi-automatic rifles such as the AR-15. In D.C. v. Heller (2011), Judge Kavanaugh dissented from his appellate-court colleagues by arguing that the rifle ban is unconstitutional.

Judge Kavanaugh’s reasoning followed Antonin Scalia’s originalist logic in Heller that the Second Amendment applies to guns in “common use.” His colleagues applied a “balancing” test that allowed them to carve a giant hole in Heller and uphold a rifle ban.

“There is no meaningful or persuasive constitutional distinction between semi-automatic handguns and semi-automatic rifles,” Judge Kavanaugh wrote in his circuit-court dissent. “Semi-automatic rifles, like semi-automatic handguns, have not traditionally been banned and are in common use by law-abiding citizens for self-defense in the home, hunting, and other lawful uses. Moreover, semi-automatic handguns are used in connection with violent crimes far more than semi-automatic rifles are.”

This upsets Ms. Feinstein, who wants to ban semi-automatic rifles, and so she asked Judge Kavanaugh “what evidence or study did you use” to determine that assault weapons were in “common use”? Mr. Kavanaugh replied: “Semiautomatic rifles are widely possessed in the United States. There are millions and millions and millions of semiautomatic rifles that are possessed, so that seemed to fit common use.”