Sen. Marco Rubio, R-Fla., endorsed Mitt Romney for president Wednesday night on Fox News' "Hannity," saying Romney offers "a very clear alternative" to President Obama's vision for the future of the country. Rubio, a young, first-termer who has been discussed as a possible vice presidential candidate, criticized talk of a fight for the Republican nomination on the convention floor, a possibility that is keeping alive the campaigns of Rick Santorum and Newt Gingrich. "I think that's a recipe for delivering four more years of Barack Obama," Rubio told Fox News' Sean Hannity. Romney has "earned this nomination," Rubio said, though...