The Koch brothers and their conservative advocacy group, Americans for Prosperity, say the Obama administration is using them as a bogeyman for the 2012 election.

Americans for Prosperity Foundation chairman and Koch Industries executive vice president Charles Koch applauds Republican presidential candidate and former Massachusetts governor Mitt Romney during the Defending the American Dream Summit at the Washington Convention Center in November. (Photo by Chip Somodevilla/Getty Images)

Obama campaign manager Jim Messina and a Koch brothers government affairs representative have sent each other dueling letters in recent days, with the Kochs accusing the Obama Administration and campaign of attacking private citizens who are simply practicing democracy, and the Obama team fighting back by casting doubt on the group’s actual grassroots support.

The Kochs initially criticized an Obama campaign fundraising e-mail that referenced their work on conservative causes, to which Messina responded by suggesting the group is more of a front for business interests and wealthy donors than a grassroots organization. Messina challenged the group to disclose its donors to prove its grassroots support.

But Phillips said doing so would only invite the Obama team to further demagogue average private citizens trying to have a voice in the political process.

“While President Obama and Messina demand lists of our supporters so they can broaden their attacks to include more private American citizens, AFP protects the identity of donors precisely because of the type of intimidation, smears, and vindictive personal attacks repeatedly launched by the President’s team on those who disagree with their big government agenda,” Phillips wrote.

AFP also accuses the Obama team of dispatching government officials to demonize it, pointing to then-Obama economic adviser Austan Goolsbee’s comments in 2010 about how the Kochs manage their tax structure.

The Obama campaign didn’t immediately respond to a request for comment.

“Americans for Prosperity now claims ‘millions’ of supporters, but can’t point to any aside from the oil billionaire Koch brothers whose special interest agenda aligns with AFP’s: zeroing out investments in clean energy, maintaining subsidies for oil and gas companies, and opposing increased fuel economy standards that save consumers money at the pump,” Obama spokesman Ben LaBolt said. “Why won’t they disclose their donors?”