Super PACs Proliferate

It didn't take long after the Citizens United case for Super PACs to begin impacting elections. The FEC ruling green lighting Super PACs occurred just a few months before the 2010 midterm elections, and it's likely that the decision helped Republicans achieve their resounding victory, which included retaking the majority in the U.S. House of Representatives.

Indeed, according to the Center for Responsive Politics, conservative Super PACs were responsible for 55 percent of all the spending by Super PACs in the midterms, while their liberal counterparts accounted for only 44 percent of total expenditures [source: Beckel].

The biggest spender -- shelling out three times as much as the second biggest spending Super PAC in 2010 -- was American Crossroads, a group founded by former Republican President George W. Bush's adviser Karl Rove. American Crossroads alone raised $28 million during the 2010 election cycle, one quarter of which came from Bob Perry, a wealthy Texas homebuilder [source: Beckel]. Another conservative Super PAC is operated by the Club for Growth, which advocates for policies that reduce regulations on businesses.

Democrat-leaning Super PACs are also multiplying. In the 2010 midterms, EMILY's List, a pro-choice group formed a Super PAC that was active (albeit unsuccessful) in trying to defeat Massachusetts Republican Scott Brown, who won a special election to replace the late Democratic Senator Ted Kennedy.

Other liberal Super PACs have also formed, including Priorities USA Action and House Majority PAC. In total, the Center for Responsive Politics says that as of September, 2011, there were 141 Super PACs, though that number was escalating quickly, with a new one being added just about every week.

So how will so many Super PACS affect the next presidential election? We'll find out next.