A shadowy political organization founded by Karl Rove is spending $750,000 to run a nationwide ad blasting workers and their collective bargaining rights. Crossroads GPS is a pro-corporate group with a history of using misleading if not outright false claims to attack Democrats and progressive causes. The organization does not disclose its donors but NBC News found that “a substantial portion of Crossroads GPS’ money came from a small circle of extremely wealthy Wall Street hedge fund and private equity moguls.”

Now, the group is out with an ad trashing organized labor on cable news in light of attempts to cut the collective bargaining rights of public employees in Wisconsin, Ohio, and Idaho. Crossroads GPS asserts that public employees are overpaid, however, a study from the Economic Policy Institute shows that public workers in Wisconsin and Ohio actually “earn lower wages than comparable private sector employees.”

Crossroads GPS isn’t the only shadowy pro-corporate group to support the GOP’s war on organized labor.

Americans for Prosperity, an organization closely tied to the Koch Brothers, is vigorously supporting Republican union-busting and unfairly blames public workers for the country’s budget problems. Like Crossroads GPS, Americans for Prosperity doesn’t disclose its donors and advocates for the agenda of corporate special interests.

As People For president Michael Keegan writes, the Supreme Court’s decision in Citizens United has empowered groups like Crossroads GPS and Americans for Prosperity to secretly use corporate money to fund pro-corporate causes:

What is perhaps most troubling about the post-Citizens United flood of corporate money in politics is the free rein it has given for corporations to hide behind front groups to run misleading ads without ever being held accountable for their content. Americans for Prosperity is now employing the same tactics it used to smear health care reform in key House districts in its ad campaign against Wisconsin unions. Like in its ads falsely claiming that health care reform hurt Medicare recipients, the group’s ads in Wisconsin pretend to champion populist values while pushing a decidedly anti-populist agenda. The ads seek not only to misinform voters, but to blame ordinary Americans for problems they did not cause.