WASHINGTON -- Senate climate change legislation took a step forward yesterday, but a move by Democrats to bypass Republicans in the environment committee could result in a political setback.

Environment and Public Works Committee Chair Barbara Boxer, D-Calif., called for a vote to move the bill from committee despite a Republican boycott of the process. By committee rules, senators could not amend the bill, but Senate rules allow a majority of members to move a bill out of committee.

Republicans have called the move "the nuclear option."

Led by Sen. James Inhofe, R-Okla., they boycotted committee meetings this week and demanded more analysis of the economic impacts of the bill by the Environmental Protection Agency. They said the agency's projections were too optimistic and did not consider enough scenarios.

EPA said a more complete analysis would take five weeks. Democrats said the request was a stall tactic, promising a full analysis before the bill gets to the Senate floor.

The controversial bill would require the U.S. to reduce emissions 20 percent by 2020 and 83 percent by 2050, and would create a cap-and-trade market in which companies could swap pollution credits.

The bill's supporters say it's imperative to act now to slow or reverse global warming, while also creating so-called "green jobs" and reducing America's dependence on foreign oil. Its opponents say it would kill manufacturing and raise energy prices at a time the country can ill afford it -- and it wouldn't make a global warming impact without the cooperation of developing nations.

The House has passed similar legislation, but the Senate is not expected to make significant headway on the bill until next year.

Given the reservations of Democrats from energy-producing states, Democratic leaders likely will need Republicans to help reach the 60-vote threshold needed to end debate in the Senate. Some have shown a willingness to make a deal on climate change -- Sen. Lindsey Graham, R-S.C., has joined Sens. John Kerry, D-Mass., and Joe Lieberman, I-Conn., in behind-the-scenes negotiations on a bill that could earn bipartisan support.

But Mr. Graham and moderate New England Republicans Olympia Snowe, Susan Collins and Judd Gregg wrote a letter to EPA Administrator Lisa Jackson this week siding with EPW committee Republicans in asking the agency for additional analysis. Ranking Republicans in other committees that will consider the bill expressed similar sentiments.

Sen. Arlen Specter, D-Pa., a member of the EPW committee who has his own concerns about the bill but still voted for it yesterday, said he doesn't think the move kills the potential for Republican support.

"This bill is going to be changed, markedly, when you move down the road, so they will get substantively what they want," Mr. Specter said.

Mr. Inhofe, meanwhile, denounced both the bill and Ms. Boxer's tactics.

"I am deeply disappointed by Chairman Boxer's decision to violate the rules and longstanding precedent of the committee," he said in a statement.

Committee Democrats voted 11-1 in favor of reporting the bill, with Sen. Max Baucus, D-Mont., the only "no." Mr. Baucus, who as chair of the Senate Finance Committee will wield sizable influence over the bill, said he is still committed to passing the legislation and will work to find 60 votes for it in the Senate. But he would like to see several alterations, including the reduction of the 20 percent emissions target by 2020 to 17 percent, unless developing countries follow suit.

Washington correspondent Daniel Malloy writes the "Pittsburgh On The Potomac" blog exclusively at PG+, a members-only web site of the Pittsburgh Post-Gazette. Our introduction to PG+ gives you all the details.