Two environmental groups working to help defeat the $7 billion Keystone XL pipeline are among those joining liberal groups Friday to protest against a tea party group previously backed by the energy-magnate Koch brothers.

The protest is directed at the annual summit meeting of Americans for Prosperity, a conservative nonprofit group that has played a leading role in promoting domestic oil and gas drilling while opposing President Obama's clean-energy agenda (see related story). Dubbed a "Guerilla Drive-in," the event is set to screen films that blast the Kochs and their eponymous energy company.

The two green nonprofits on hand for the event, Tar Sands Action and Oil Change International, both have worked against the Canada-to-U.S. Keystone XL project -- which one senior Democrat has said could represent a notable bottom-line boost to the Kochs (E&ENews PM, Oct. 18).

Koch Industries, run by conservative brothers Charles and David Koch, has strongly denied that it stands to gain from approval of the Canadian oil sands crude pipeline and sought to distance itself from Americans for Prosperity. On the company's website, it notes that "less than 10 percent" of that nonprofit group's 2009 funding came from Koch-related coffers.

Nonetheless, the Kochs' appeal as a political symbol of fossil fuel wealth extends beyond environmentalists. Other liberal groups scheduled to be on hand for the Friday protest include USAction, Public Citizen and Common Cause.