Tony Perkins is urging Senator John Cornyn to withdraw from a scheduled appearance next week at an event for gay GOP group Log Cabin Republicans.

It would be difficult to label the Texas senator gay friendly – he opposes repeal of the military's ban on open gay service (“Don't Ask, Don't Tell”) and government recognition of gay unions – but Perkins, president of the social conservative Family Research Council, is concerned that his presence would undermine conservative values.

“[I]t is deeply troubling to me that you would lend your credibility to this organization,” Perkins said in a letter addressed to Cornyn.

Last week, the Log Cabin Republicans convinced U.S. District Judge Virginia Phillips to declare “Don't Ask, Don't Tell” unconstitutional. The Justice Department has yet to announce whether it will appeal the law.

Perkins decried the ruling as a “blatant example of judicial activism.”

“I … want to express my profound disappointment in the fact that you are assisting the very organization that sought this decision from Judge Phillips,” he said.

“How can a group that professes allegiance to the GOP at the same time be committed to using judicial activism to advance its radical social policies even at the risk of undermining the U.S. military and, as a result, national security?”

Cornyn defended his decision to attend the September 22 fundraiser, saying it was important to engage with “adults with whom we may disagree.”

“Respecting each other's dignity is not about ignoring those disagreements, but rather being honest about them, and working together where possible despite them,” he said in a response to Perkins.

Other Republicans expected to attend the fundraiser to be held at Washington's Capitol Hill Club are representatives Pete Sessions of Texas, Joseph Cao of Louisiana, Charles Djou of Hawaii, Ileana Ros-Lehtinen of Florida and Judy Biggert of Illinois.