The most vocal critics of the Supreme Court's Citizens United decision in 2010 turned out to be also the law's most skillful exploiters, according to the Atlantic's Molly Ball.
Despite liberal loathing of the super PAC concept, Democratic superPACs like Priorities USA was more successful at driving the campaign narrative against Mitt Romney, although it was vastly outspent by Karl Rove's superPAC American Crossroads. So successful was Priorities that they're continuing their activities post-election, and are now pressuring swing-vote Congressmen to not compromise in fiscal cliff talks.
Citizens United also freed up unions to exert more influence. In the past, unions were only allowed to communicate politically within their organizations, and not with the general public, explains Michael Podhorzer, political director of the AFL-CIO. The Citizens United decision was like "taking off the handcuffs" Podhorzer said.
For all the outrage over conservative superPACs, the liberal variant received scant negative attention: "We got very little blowback at all," Becky Bond, director for a progressive super PAC, told the Atlantic. "People were very excited that this was our superPAC. People thought the superPAC was super."Via the Atlantic