Despite his moderate reputation, Ives supported the Taft–Hartley Act in 1947 and voted to override President Harry S. Truman's veto of it; he subsequently lost his longstanding support from labor unions. He served as a delegate to the 1948 Republican National Convention in Philadelphia, Pennsylvania, which nominated his friend and fellow liberal New Yorker Thomas E. Dewey. That same year he married his longtime secretary, Marion Mead Crain.