Knowledge of the process is limited to a few of Romney's highest-level aides. Information is on a "need-to-know" basis — and as far as those aides are concerned, there are few people inside the Boston headquarters who need to know, let alone reporters and other outsiders.
The process is so secret because it's so sensitive.
A vice presidential vetting is possibly the most intense background check in politics. Everything is fair game: voting records and the political past, to be sure, but also personal issues.
"I think everyone should take a deep breath," Rubio said Tuesday. "Here's the one thing everyone should know: Gov. Romney's going to make a great choice. In that I'm confident."