A former presidential candidate, Perry was one of the first this election cycle to use Romney's former firm, Bain Capital, to knock the former Massachusetts governor. Perry made headlines when he accused Romney of "vulture capitalism" and repeatedly targeted him as a greedy corporate raider.

Newt Gingrich also jumped on the Bain train during the primary, though he soon backed down, following a backlash of Republican scorn over attacking the business world.

Now, Democrats, including the president, are using Romney's private sector experience to cast the presumptive GOP presidential nominee as unqualified for the Oval Office, arguing the job of the president is to look out for all Americans, not simply maximize profits.