The U.S. Chamber of Commerce isn’t laughing after political-pranksters The Yes Men staged a fake press conference at the National Press Club in mid-October, supposedly announcing the Chamber’s new approach to climate change policy. The Chamber filed suit Oct. 26, alleging the group infringed on its trademark by displaying the trade group’s logo on a podium and creating a fake Web site that mirrored and even linked to the Chamber’s own to mislead the public about the Chamber’s views.

“The defendants are not merry pranksters tweaking the establishment,” said Steven Law, the Chamber’s chief legal officer and general counsel, in a press release. “These acts are nothing less than commercial identity theft masquerading as social activism and must be stopped.”

The Yes Men imply on their Web site they’ve been sued before and had the cases dismissed.

“It’s shameful that the Chamber has decided to lash out at a public interest group like ours for trying to push back and call attention to the Chamber’s outrageous positions,” The Yes Men said in a statement responding to the Chamber’s suit.