A left-leaning group, Patriot Majority, has launched a $500,000 ad campaign trying to make an election issue out of conservative mega-donors David and Charles Koch, suggesting the brothers are spending big "to buy this year's elections and advance their agenda," with the goal of electing "politicians who will pass laws that benefit special interests but hurt the middle class."

The half-million dollar ad buy is reportedly the beginning of a long-term, multi-million dollar campaign aimed at raising public awareness of the Koch brothers and conservative special interests.

Although the billionaire Koch Industries heirs are among the country's largest donors to Republican candidates and right-wing organizations like the American Legislative Exchange Council and Americans for Prosperity -- which David Koch co-founded and chairs and which is led by one of his right-hand men -- the pro-Democratic group behind the ads, Patriot Majority, says the brothers have less name recognition among the general public than is warranted. "We believe that the more people learn about the Koch brothers and their agenda, that there is going to be a very positive response," Patriot Majority's president Craig Varoga told Politico. "Instead of complaining about the money that they're spending, we're going to focus on the policies that their front groups are actually pursuing and that is a significant difference from what has been done in the past."

The first round of ads, which are scheduled to run on various cable news networks including CNN and MSNBC, tell viewers that the goal of the Kochs' political largesse includes: "More tax cuts for the rich. Eliminate the minimum wage. Big cuts to our schools, but big subsidies for oil companies. Tax breaks for corporations that ship our jobs overseas."

The ad includes an image of a check made out to the "Greed Agenda" from Koch-funded groups Americans for Prosperity and ALEC, and directs viewers to the website "StoptheGreedAgenda.com."

The organization behind the ads is the 501(c)(4) nonprofit arm of Patriot Majority, which also has a "Super PAC" associated with U.S. Senator for Nevada Harry Reid. The group is run by Varoga, a Democratic political strategist widely credited with Harry Reid's hard-fought victory in 2010. Politico recently described him as the "consummate insider: Most people have never heard of him, but he's had his hand in critical Democratic races for more than 20 years."

As a 501(c)(4), under current rule interpretations, the nonprofit does not have to disclose the identities of their donors, as with other non-profit groups, such as Koch's Americans for Prosperity Foundation and Karl Rove's Crossroads GPS operation, right-wing groups which are poised to spend hundreds of millions of dollars in this election cycle. In response to past criticism that Varoga is playing the same dirty games as right-wing groups, he said, "We have to play the cards we're dealt because otherwise, if we whine and complain, [we] will be completely disadvantaged, and we will lose races that otherwise we should win."

Koch Industries recently issued a response to these ads using an attack they and their allies have repeatedly tried to claim: that, purportedly, opponents speaking are out against them are an "attempt to shut down free speech."