Thousands of protesters marched on Michigan's capitol in Lansing to protest the state legislature's passage of right-to-work legislation, which bans requiring employees to join a union or pay union dues to stay employed. Michigan Gov. Rick Snyder (R) signed the legislation into law on Tuesday evening, a few hours after the bill passed the state legislature.

Obama has criticized the legislation, and Carney reiterated that on Thursday.

"Right-to-work laws are really right-to-be-paid-less laws, and they reflect a political agenda not an economic agenda," Carney added.