Liberal action group launched a fundraising plea Monday to target centrist Democrats who are demanding changes to the Waxman-Markey climate change bill.

The group, which more frequently targets Republicans than Democrats, sent an email to supporters asking them to help raise $192,000 to air ads in the districts of centrist Democrats who are holding up passage of the lgislation.

"We've only got one shot at at this thing. If the bill gets watered down now, it'll be really hard to strengthen it later," the group wrote to supporters. "So we've put together an ad to run in key Democrats' home districts, showing how clean energy can rebuild the American economy one community at a time."

In particular, the group is focusing on swaying at least four centrist Democrats named in a New York Times report last week as opponents of the climate change legislation in its current form: Reps. Rick Boucher (D-Va.), Mike Doyle (D-Pa.), Charles Melancon (D-La.), and Charles Gonzalez (D-Texas).

"MoveOn's got a critical role to play in supporting and strengthening the bill