July 12 (Reuters) - U.S. Senator Lindsey Graham, a Republican who went from a vocal critic of Donald Trump to one of his most loyal allies after Trump became president, has died, his office announced on Sunday. He was 71. The South Carolina lawmaker died after a "brief and sudden illness," his office posted on X. U.S. media said emergency personnel had responded to a call for cardiac arrest at his Capitol Hill home in Washington on Saturday night.