Key findings:

Crossroads GPS is a nonprofit 501(c)(4) organization, a name that comes from the IRS tax code. They can raise and spend up to 49 percent of their funds attacking or supporting candidates, but cannot contribute directly to a campaign.

— Unlike a super PAC, donations to nonprofits can remain completely anonymous. Super PACs, such as American Crossroads, must disclose donors' names and amounts contributed, which most do either once a month or once a quarter.

— Both Crossroads organizations, which are associated with former Bush adviser Karl Rove, are on the front lines of political spending. They hope to raise at least $240 million total during the 2012 election cycle, a figure that would more than triple the amount they raised ahead of the 2010 midterm election.

— Steven Law, the president of both Crossroads groups, made a combined $1.09 million between June 2010 and December 2011.