Senate leaders and the White House are continuing to explore whether to push energy legislation on the Senate floor before the midterm elections this November. Senator Harry Reid, the Nevada Democrat and majority leader, was meeting Thursday afternoon with the chairmen of the committees with jurisdiction over energy issues to plot strategy.

Leading Democrats see the threat of E.P.A. action as an effective way to keep pressure on Congress to consider energy legislation and as a ready alternative if the House and Senate are not able to come to terms on an energy measure.

Supporters of the plan to block the E.P.A. said they were trying to stop a backdoor attempt by the Obama administration to regulate carbon emissions without waiting for Congress to weigh in. They said the E.P.A. approach would produce little environmental reward while putting the United States at a severe disadvantage to nations that were not imposing such controls on their own industries.

“It would be stupid for us to do this now when the rest of the world is not coming along at all,” said Senator Tom Coburn, Republican of Oklahoma. “Even if it is the right thing to do, now is not the time to do it.”

Though Mr. Coburn said the case for global warming is not settled science, several other Republicans said they accepted the scientific assessment that climate change is occurring. They said their main reason for trying to rein in the E.P.A. was concern over handing such far-reaching regulatory power on emissions to an executive agency.

Given that several backers of Ms. Murkowski’s plan said they believed climate change was a reality, senators advocating a broad energy approach that would try to address global warming said defeat of the plan to strip the E.P.A. of regulatory authority over greenhouse gases should provide momentum to their legislative efforts.

“Climate change is happening,” said Senator Joseph I. Lieberman, an independent from Connecticut who is a sponsoring a main climate change bill with Senator John Kerry, Democrat of Massachusetts. “The science is convincing and the current pattern of energy consumption is just making a bad problem worse.”