Will a longtime friend of Marco Rubio’s compromise his larger ambitions?

On April 19, Republican Senator Marco Rubio appeared at a policy breakfast in Washington. The ostensible topic was his proposal for a Republican alternative to the DREAM Act, but it wasn’t long before the conversation drifted to vice presidential talk. Since the start of the Republican primary, Rubio has been named at the top of nearly every short list of likely running mates—and for good reason. He is young, charismatic, and popular with both the Tea Party and the GOP establishment. He has a reputation for being serious about policy. He is a Hispanic in a party that badly needs to do better with Hispanic voters. And it hardly hurts that his home state is Florida.

Of course, when the inevitable question arose, Rubio declared in his surprisingly youthful voice, “I don’t want to be the vice president right now.” Was it because he was too inexperienced, the interviewer asked? Rubio, a lively speaker with a canny sense of comic timing, said no. “I’m older than I look,” he explained. “I’ll be forty-one this year, but I feel forty-two.” Later, he said: “Three, four, five, six, seven years from now, if I do a good job as vice president—I’m sorry—if I do a good job as a senator ...I’ll have the chance to do all sorts of things.” The gaffe was striking not least because it was a rare moment in which Rubio seemed to be caught off-balance. But Rubio was adamant that he wasn’t angling to be on the presidential ticket. “I think the Senate is a very valid place to shape and drive American policy, foreign policy, which I enjoy deeply,” he said. “If I were running for vice president, I would have to answer questions about my dog.”

All of these coy denials only seemed to heighten Republican interest. And, in the following days, Rubio did all the things one would expect of someone who wanted to be vice president: He gave a well-received foreign policy speech at the Brookings Institution and appeared with Mitt Romney, by that point the all-but-certain nominee, at a campaign event in Pennsylvania. But, in the midst of this media blitz, there was one bit of news that didn’t quite fit: Politico reported that Rubio was planning to hold a fund-raiser at an upscale Capitol Hill restaurant for a Florida congressman named David Rivera.

Given that conservative excitement over Rubio was approaching fever pitch, it was a strange move indeed. For a year and a half, Rivera had been under criminal investigation by the Florida Department of Law Enforcement and the Miami-Dade Office of the State Attorney. In September, Citizens for Responsibility and Ethics in Washington had named him one of the 19 most corrupt members of Congress. Rivera, in short, was not the kind of person for whom someone auditioning to be vice president would want to hold a fund-raiser.

But Rivera also happens to be Marco Rubio’s closest friend in politics. And, during the course of their friendship of 20 years, he has been instrumental in Rubio’s rapid rise from West Miami commissioner to U.S. senator. A Republican colleague in the Florida House describes their relationship as “one step below blood.” As a result, if Rubio makes it on to the Republican ticket, questions about his dog may be the least of his problems.