BUYING ELECTIONS WITH FOREIGN FUNDS?…. President Obama recently delivered a speech warning of a “corporate takeover of our democracy” in the post-Citizens United landscape, with shadowy groups raising millions in secret to help buy elections for Republicans.

“None of them will disclose who’s paying for these ads,” the president said. “You don’t know if it’s a Wall Street bank. You don’t know if it’s a big oil company. You don’t know if it’s an insurance company. You don’t even know if it’s a foreign-controlled entity.”

That last point is of particular interest, since the idea of foreign funds buying elections probably strikes most Americans as problematic. With that in mind, ThinkProgress has a fascinating item today.

The largest attack campaign against Democrats this fall is being waged by the U.S. Chamber of Commerce, a trade association organized as a 501(c)(6) that can raise and spend unlimited funds without ever disclosing any of its donors. The Chamber has promised to spend an unprecedented $75 million to defeat candidates like Jack Conway, Sen. Barbara Boxer (D-CA), Jerry Brown, Rep. Joe Sestak (D-PA), and Rep. Tom Perriello (D-VA). As of Sept. 15th, the Chamber had aired more than 8,000 ads on behalf of GOP Senate candidates alone, according to a study from the Wesleyan Media Project.

The Chamber’s spending has dwarfed every other issue group and most political party candidate committee spending. A ThinkProgress investigation has found that the Chamber funds its political attack campaign out of its general account, which solicits foreign funding. And while the Chamber will likely assert it has internal controls, foreign money is fungible, permitting the Chamber to run its unprecedented attack campaign. According to legal experts consulted by ThinkProgress, the Chamber is likely skirting longstanding campaign finance law that bans the involvement of foreign corporations in American elections.

The Chamber’s political activities are an ongoing point of interest here, but ThinkProgress’ research raises new questions. The Chamber has been raising money hand over fist to influence the outcome of congressional elections, and to boost its coffers, it’s sought out funds from foreign corporations and businesses run by foreign governments.

The result is an unwelcome development for the American political system: an interest group is spending $75 million this year to boost Republicans, but not all of that money is American money. Indeed, some of the attack ads you’ve seen from the Chamber may very well have been financed, at least in part, by foreign governments.

Are voters O.K. with this? Is it the kind of development that might draw legal scrutiny?

For what it’s worth, a spokesperson for the U.S. Chamber of Commerce quickly responded to the news, telling Politico that it’s “careful” to comply with the law and that it has “a system in place for ensuring that they are not government-controlled entities.”

What kind of system? It didn’t say. There’s nothing like vague, terse responses from an already-secretive, conservative lobbying group to set minds at ease.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.