Casino mogul to give at least $10 million more for campaign gifts

Sheldon Adelson, a wealthy casino owner, is committing to give at least an additional $10 million to conservative groups expected to play a major role in this year’s presidential and congressional elections, cementing his growing role as one of the country’s leading political financiers.

Adelson — who has already donated more than $30 million this year to super political action committees backing Newt Gingrich, who dropped out of the presidential race last month, and Mitt Romney, who is now the Republicans’ likely nominee — is quickly expanding his giving to a variety of Republican-leaning organizations, including tax-exempt issue advocacy groups that are expected to spend most of the outside money in this year’s campaigns.

He has committed at least $10 million to the Crossroads Grassroots Policy Strategies, founded by Karl Rove, according to people with knowledge of his donations. He has discussed contributing another $10 million to groups aligned with Charles and David Koch, the billionaire oil and chemical executives who founded Americans for Prosperity, another issue group.

Such organizations, known as 501( c)( 4) groups after the section of tax law under which they are organized, are not allowed to engage in fulltime campaign activity. And unlike super PACs, they are not required to disclose their donors. But the groups have already spent tens of millions of dollars on issue ads, much of it on behalf of Republican candidates or against President Barack Obama.