Is he worried about debating Vice President Biden? Florida Sen. Marco Rubio said Wednesday he would turn down the vice presidency if asked—most likely. Rubio, who is a rising star in the GOP from a key swing state, has long been considered a top favorite among Republicans for vice president. At a Washington conference, Rubio praised the Senate for its work and said he didn’t believe in using his seat as a “launch pad” for higher political office. Republicans will pick the vice-presidential candidate in September 2012, after the nominee is selected.