(Newser) – The $10 million Sheldon Adelson spent on Newt Gingrich's failed presidential campaign may have been just a warmup. The casino billionaire has donated $10 million to pro-Romney super PAC Winning Our Future, making him and his wife, Miriam, this election's biggest donors by far, sources tell the New York Times. Adelson has a $25 billion fortune, and he has said he would be willing to spend as much as $100 million on this year's election.

Adelson is prepared for "limitless" spending because he believes no price is too high to protect the US from Obama's "socialization," and to secure the safety of Israel, say sources close to Adelson. "I’m against very wealthy ­people attempting to or influencing elections," the billionaire told Forbes in March. "But as long as it’s doable I’m going to do it."