Must-read from Fredreka Schouten and Mary Troyan USA Today:

The Alabama political scandal that has cost the state’s governor his marriage and now threatens his job has thrust politicians’ growing use of often-secretly funded nonprofits into the spotlight.

Gov. Robert Bentley’s former aides created the tax-exempt Alabama Council for Excellent Government last year to promote the governor’s agenda, but some of its funds went to pay the governor’s senior political adviser, exposed in recent weeks as his extramarital love interest. And like any other “social-welfare” group created under the 501(c)(4) section of the tax code, it does not have to disclose its donors.

Nonprofit groups have become a fixture in federal politics, allowing secret donors to pump unlimited sums into advertising and get-out-the-vote efforts in elections. But their use has spread rapidly to statehouses from Lansing, Mich., to Nashville, Tenn., and city halls from New York to Los Angeles, as another source of cash that elected officials of both parties can tap to help shape public policy.