Former Alaska Governor Sarah Palin, who was John McCain's vice presidential nominee in the 2008 elections, is endorsing Republican front-runner Donald Trump for president. "I'm proud to endorse Donald J. Trump for president," Palin said in a brief statement released by Trump's campaign. Palin, who remains an influential voice among conservatives, will join Trump at a rally in the city of Ames in Iowa at 5 p.m. CT (6 p.m. ET) on Tuesday to personally announce her endorsement.