Some activists at the Public Broadcasting Service seem jealous that CNN is alone in offering yet more free debate time to the Democrats. Last year, PBS offered a liberal debate forum to both parties, hosted by black activist Tavis Smiley. Cornelia Dean reports on The Caucus blog at The New York Times that some PBS producers want a science debate between the Democrats with a group called Science Debate 2008: 

Senators Hillary Rodham Clinton and Barack Obama have turned down a chance to debate science issues next week in Philadelphia, but the would-be organizers, a group of scientists and others called ScienceDebate2008, hope to arrange an alternative in Oregon, which holds primaries May 20.

Ty West, senior producer for the PBS weekly news program NOW, said he has been working with the group in hopes of scheduling a debate either May 2 or May 9 to be broadcast by the Public Broadcasting System from Portland State University. He said the effort was a cooperative effort involving WNET in New York, which produces NOW, WGBH in Boston, which produces the science program NOVA, and WOPB, the public broadcasting station in Portland.