Meet the biggest donors of the 2012 campaign

  • Sheldon Adelson, Peter Thiel, Foster Friess and Jeffrey Katzenberg CBS/Getty Images

    Updated with February's super PAC financial reports.

    To understand just how important so-called "super PACs" have become, consider this: The super PAC backing Newt Gingrich raised more than $5 million more in January than what was raised by Gingrich's own campaign.

    The fact that super PACs are getting bigger than the campaigns they're there to support is a big deal - particularly when the super PACs are funded in large part by one or two large donors. In Gingrich's case, that donor is Las Vegas casino magnate Sheldon Adelson, who (along with his wife) gave Gingrich's super PAC $10 million of the $11 million it raised in January.

    Super PAC donors by the numbers

    Adelson's largess powered advertising on Gingrich's behalf in key states and allowed the candidate to focus his own resources on the nuts and bolts of campaigning.  It's an open question whether Gingrich would still be in the race had Adelson not opened his checkbook.

    Gingrich is not alone: Mitt Romney's campaign ended January with less than $8 million in cash on hand. The super PAC backing him has $16.3 million, according to FEC reports.

    In the super PAC age, there are no limits on how much a well-heeled individual can spend to get a candidate elected (or defeated). Click through to meet some of the notable people who are spending big to influence elections past and future - a group that includes at least 21 billionaires - in order of how much they've given in this campaign cycle. 

    FIRST UP: Sheldon Adelson