"U.S. Sen. Marco Rubio, right, argues with Jeb Bush during a <a href=""http://www.cnn.com/2015/10/28/politics/gallery/republican-debates-colorado/index.html"" target=""_blank"">Republican debate</a> in Boulder, Colorado, on Wednesday, October 28. Bush went after Rubio for missing votes in the Senate while running for the White House. ""Just resign and let someone else take the job,"" Bush said. Rubio fired back, saying Bush never took issue with Sen. John McCain missing votes when he was running for President. ""The only reason you're doing it now is because we're running for the same position."""