President Bush withdrew his nomination of Sam Fox, a top Jewish Republican, to be ambassador to Belgium. Democrats on the U.S. Senate’s Foreign Relations Committee had denounced Fox’s contributions to Swift Boats Veterans for Truth, a group that had questioned the Vietnam War service record of Sen. John Kerry (D-Mass.), the Democratic candidate for president in the 2004 election. Bush withdrew Fox’s nomination Wednesday hours before members of the Foreign Relations Committee were to vote on it. Kerry and others on the committee said they could not accept Fox’s explanation during confirmation hearings for his $50,000 contribution to the group. Fox said he considered Kerry a hero, but added that “when I’m asked, I just generally give.” He refused to apologize for the donation. Fox, 77, of St. Louis, Mo., is national chairman of the Republican Jewish Coalition.