Marco Rubio blasted Rand Paul but said Jeb Bush would be a credible candidate if the former Florida governor decides to run for president. On ABC's "This Week," Florida's Republican senator said he had not decided whether to seek the White House in 2016. "Jeb is going to be a very -- if he decides to run, he is going to be a very credible and a very significant candidate in this race," Rubio told George Stephanopoulos. "I have tremendous respect for him."