(Reuters) - U.S. Senator Marco Rubio said on Wednesday that he was running for re-election in part to provide a counter-weight to whomever might win the White House in November, whether Democrat Hillary Clinton or Republican Donald Trump. Rubio criticized Clinton in a statement he released to explain his decision, but added: “The prospect of a Trump presidency is also worrisome to me.” “If he is elected, we will need senators willing to encourage him in the right direction, and if necessary, stand up to him. I’ve proven a willingness to do both,” Rubio said. 