Republicans are combing Tim Walz’s record for misstatements.

Seeking to blunt the momentum that Vice President Kamala Harris and her running mate, Gov. Tim Walz of Minnesota, have been experiencing in the polls and hoping to extend after an enthusiastic Democratic National Convention, Republicans have been highlighting small inaccuracies in Mr. Walz’s past descriptions of his résumé.

The latest instances came on Friday and Saturday, when the right-leaning Minnesota outlet Alpha News and the conservative publication The Washington Free Beacon resurfaced reports from 2006 that, while Mr. Walz was running for Congress that year, his website inaccurately stated that he had been named “Outstanding Young Nebraskan by the Nebraska Chamber of Commerce.”

After the Nebraska Chamber of Commerce sent Mr. Walz a letter in late 2006 saying that it had not given him an award and noting that the U.S. Chamber of Commerce had endorsed his Republican opponent, his campaign clarified that the award had come from the Nebraska Junior Chamber of Commerce, and updated his website accordingly. His campaign manager at the time said the missing word had been an unintentional typo.

Beyond the 2006 award reference, Republicans have accused Mr. Walz of exaggerating his military service record. This campaign is reminiscent of the “Swift Boat” attacks against John Kerry, a decorated Vietnam War veteran who was the Democratic presidential nominee in 2004 — and Chris LaCivita, a top aide to former President Donald J. Trump, led the Swift Boat campaign.

Republicans have noted that the Harris campaign’s website described Mr. Walz as a “retired command sergeant major.” While Mr. Walz did attain the rank of command sergeant major during his 24 years in the Minnesota National Guard, he didn’t complete coursework required for him to retain the rank after retiring. The website was edited to describe him as “rising to the rank of command sergeant major.”

The Harris-Walz campaign has also said Mr. Walz misspoke when he said in 2018, in the context of calling for restrictions on assault weapons, “We can make sure that those weapons of war that I carried in war is the only place where those weapons are at.” He did not serve in a combat zone; the campaign said he had meant to convey that he had handled such weapons while serving in the National Guard.