MoveOn.org began circulating a petition this morning to try and block Fox News from hosting a Democratic presidential candidates' debate. The liberal-leaning activist group's civic action arm called Fox "a right-wing mouthpiece" that repeats "false Republican talking points to smear Democrats."

"Fox is a mouthpiece for the Republican Party, not a legitimate news channel. The Democratic Party of Nevada should drop Fox as its partner for the presidential primary debate," reads the petition, which is being circulated via e-mail and on Web sites.

"If ever there was a battle where we could beat Fox, this is it -- since Democrats will make the ultimate decision, not Fox executives," MoveOn says in the e-mail. "But to be convinced, Democratic leaders need to see a growing public backlash."

Fox announced recently it would host a meeting of the Democratic contenders in Reno on Aug. 14.

The move irritated dozens of liberal bloggers who began their own campaign to try and get Nevada officials to reconsider.

CNN, which is doing its own Nevada debate in November, was rumored to have turned the offer down to host the August debate as well.

-- Christina Bellantoni, Capitol Hill correspondent, The Washington Times