Adelson has already pledged $10 million in additional funds to Crossroads GPS, and advocacy organization helmed by former Bush adviser Karl Rove, and another $10 million to two separate groups backing House GOP candidates. Including donations to Newt Gingrich's campaign, the casino billionaire has spent more than $70 million on the 2012 race already, the Huffington Post reports.

Some of that money could be coming back, though. According to the June filing from Winning our Future, the super-PAC supporting Gingrich's effort, the committee is refunding $5 million to Adelson's wife, Miriam. Gingrich exited the presidential race in May.