The measure, which an aide said could move either as part of a comprehensive climate bill or separately, would strip the Environmental Protection Agency of all its existing authority to regulate greenhouse gas emissions.

Voinovich, who will retire at the end of 2010, circulated a draft bill Wednesday that would eliminate existing EPA authority to regulate GHGs for their contributions to global warming not only under the Clean Air Act, but the Clean Water Act, National Environmental Policy Act, Endangered Species Act, and any other existing environmental law.

"Because climate change is a global issue, I believe that addressing climate change effectively must be done through a single, national program that replaces the existing, conflicting patchwork of rules, regulations, and lawsuits," Voinovich said in a statement accompanying the bill.

"To get my support on any climate change legislation, it must include a comprehensive pre-emption provision that goes well beyond language included in previous climate bills," he added.

An aide to the senator said the pre-emption language was a starting point, not an ending point, and while Voinovich would not consider any legislation that did not include broad pre-emptive language he would also look for generous provisions for coal-fired electrical generation and other policies he believes will be helpful to manufacturing states.

Democrats stand to lose between five and ten of their own members if they bring a bill to the Senate floor that places a price on carbon emissions, and moderate Republicans like Voinovich are considered key players both in providing the necessary votes for a mandate and in giving Democrats the political cover they need to vote for the bill themselves.

--Jean Chemnick, jean_chemnick@platts.com