A federal judge has dealt a blow to political groups who try to keep their donors anonymous.

U.S. District Judge Amy Berman Jackson says the FEC overstepped its authority when it ruled in 2007 that corporations and nonprofits did not have to reveal the identity of their donors when those groups spend money on ads that don't advocate for or against a candidate.

From Fox News -

In her 31-page ruling, Jackson said the FEC did not have legislative authority to substantially change McCain-Feingold, officially known as the Bipartisan Campaign Reform Act of 2002. She said it is up to Congress, not the FEC, to make such changes.

The FEC, created in the 1970s in the wake of the Watergate scandal, is empowered to set regulations on campaign-finance law and enforce subsequent violations. The commission has struggled in recent months to define new regulations, largely due to a bitterly divided makeup of three Republican and three Democratic commissioners.

Under McCain-Feingold, groups that spend more than $10,000 per year on such campaign ads must file reports with the FEC. Some groups later testified before the FEC that disclosing all donors - not just ones who specifically earmarked their money for ads - would be an administrative burden.