We've written before about how Sen. Pat Toomey intends to strike a different path than his predecessor, Arlen Specter, and today marks a particularly vivid example: Toomey has signed on as an original co-sponsor of Jim DeMint's national Right to Work legislation. Specter courted unions throughout his time in the Senate but this move from Toomey signals that he doesn't intend to lock arms with the AFL-CIO anytime soon -- a sign both of Toomey's conservative economic ideology and of unions' waning power.

Right-to-work legislation basically prevents union-only workplaces, which would erode union membership. It's the political opposite to the Employee Free Choice Act, which would have made it easier for unions to organize.

In addition to DeMint, five other Republicans -- Orrin Hatch and Mike Lee (Utah), Rand Paul (Kentucky), Tom Coburn (Oklahoma) and Jim Risch (Idaho) -- have signed on. All but Paul and Toomey come from states with right-to-work laws already in place.

Expect the union backlash to be swift. AFL-CIO spokesman Eddie Vale tweeted "Pat Toomey just complicated his pretend I'm moderate so i can get re-elected act."