Matthew Continetti writes for the Washington Free Beacon about Democratic presidential nominee Kamala Harris’ first major decision.

The final month of election 2024 begins with J.D. Vance triumphant, Tim Walz wounded, and the presidential race too close to call. By now, it should go without saying that Walz bombed in Tuesday’s debate with Vance. The Democratic vice presidential nominee appeared nervous and uncomfortable and uncertain of how to respond to the conflict between Israel and Iran. He hardly landed a blow on the youthful, confident, fluent, and unflappable Vance until the final minutes of the bout. Walz spoke too fast, made silly faces, and squirmed when confronted with the fact that for years he’d been lying about visiting Hong Kong during the Tiananmen Square protests in 1989. “I’m a knucklehead at times,” Walz blurted.

That’s an understatement. Walz is more than a knucklehead. He’s a liability. Why? Because vice presidential nominees take an electoral version of the Hippocratic Oath: Do no harm to the top of the ticket. Walz had a good rollout and a quick and effective speech at the Democratic National Convention. He entered the debate with positive favorable ratings. Yet he’s become a distraction for Kamala Harris and her campaign. Walz is a walking reminder that Harris’s judgment is questionable at best.

The problems began with evidence that Walz misrepresented his military service. They mounted with further evidence that Walz inflated additional items on his résumé. The campaign limited Walz’s contacts with the media, fearing that he might display ignorance or misalignment with Harris’s deliberately vague message. His stances on racer and gender identity and, as J.D. Vance pointed out, abortion undercut the soft-focus moderation Harris is selling in TV ads and interviews. Nor do his selfies with far-left scion Alex Soros reinforce Walz’s preferred image as the aw-shucks football coach from Mankato.