Who’s buying elections? Based on new trends toward anonymous contributions to political groups, it’s harder than ever to tell. As Politico reports:

The full extent of the anonymous giving is by definition impossible to know. But the recent disclosures as well as interviews with fundraising sources suggest that Republican-allied independent groups are outpacing Democratic ones in collecting undisclosed contributions to fund their political advertising, just as they did in 2010.

But, perhaps more significantly, they show that Democrats, who vociferously attacked that kind of fundraising last year, have set aside their qualms and are now active competitors in the anonymous donor arms race.

The report says that Priorities USA, American Bridge 21st Century Foundation, and Patriot Majority collected at least $3.7 million in untraceable contributions in the first half of the year for Democratic efforts. Even though groups that disclose donors raised more than that amount, some analysts are speculating that anonymous donations will play a large role in the next election cycle.   Meanwhile, Republican groups continue to utilize anonymously funded political advertising through groups such as the U.S. Chamber of Commerce, Crossroads Grassroots Policy Strategies, and the 60 Plus Association.

These groups, registered as “social welfare organizations” under section 501(c)(4) of the tax code, are not allowed to directly coordinate their spending with specific candidates, but they still contribute to the overall efforts and platforms of the politicians. Unlike direct contributions to campaigns, which are subject to more federal regulations and limits, these organizations are able to accept unlimited contributions from anonymous individuals as a result of Citizens United v. FEC .   It is possible that the Democrats are only using these groups because they know the Republicans are, and they don’t want to be outspent. Even so, the shady new contributions strategies by both parties mark a departure from Obama’s statement last October: “The American people deserve to know who’s trying to sway their election.”