Donald Trump’s running mate, Sen. J.D. Vance (R-Ohio) — a military veteran — has publicly challenged Democratic rival Tim Walz’s military service record. What Happened: On Tuesday, Vance took to X to respond to Walz’s comments at the American Federation of State, County and Municipal Employees union convention. Walz, who recently became Kamala Harris‘ vice-presidential candidate, had defended his military record, stating, “I am damn proud of my service to this country.” “I’m going to say it again as clearly as I can: I am damn proud of my service to this country, and I firmly believe you shoul…