Missing was Senator Lindsey Graham, the South Carolina Republican who had worked with the two New Englanders on the bill until a few weeks ago. Graham opted to stay away because Democratic leaders have said they wanted to put a rush on immigration reform legislation. But his presence was felt in the content of the climate-change bill, which takes a sector-by-sector approach to cutting carbon emissions and provides rebates to consumers to soften the impact of higher energy prices.

Under the bill, carbon emissions would be cut by 17 percent in 2020 and by more than 80 percent in 2050.

The legislation also calls for investments in renewable energy, while providing incentives for nuclear power, clean-coal technologies, and even offshore drilling for oil. States would receive 37.5 percent of revenue from new offshore oil and gas leases in areas that previously were off limits.

New protections were added to the bill’s drilling section, however, following the catastrophic oil spill in the Gulf of Mexico. The legislation provides states with the right to ban drilling within 75 miles of their coastline. If Interior Department studies show nearby states could be affected by an oil spill, they could block new offshore oil wells as well.

The bill was a product of six months of consensus-building efforts, which Kerry said vastly improved the bill’s chances.

Companies that opposed every previous bill to cap carbon emissions support this legislation, he noted. Kerry said several Republicans have told him privately that they like the bill’s approach.

“The path to 60 votes in the Senate has been long, but despite Washington conventional wisdom, we are closer than ever to a breakthrough,” the Massachusetts Democrat said. “We’re going to get it done this year.”

“We would not be here today if we did not feel that, with the help of the people here, we can and will adopt the America Power Act in this session of Congress,” said Lieberman, an Independent from Connecticut.

Jim Rogers, chairman and CEO of Duke Energy, was one of the people standing with Kerry and Leiberman. The electric utility executive said the legislation “gives our industry the road map we need to go forward.” It will lead to a clean system of power generation “in a manner that protects family budgets and protects American factories that depend on affordable power,” he said.

The legislation sets a floor and a ceiling for the price of carbon and establishes a system for selling and trading carbon permits among electric utilities, large manufacturers, and other major emitters of greenhouse gases.

Reaction from Washington’s lobbyists for the business community was mixed. The U.S. Chamber of Commerce, which has been reviled by environmentalists for its opposition to previous cap-and-trade bills, said it appreciated the work of the three senators “to constructively engage the business community on these issues.”

But the bill is a “work in progress,” noted Bruce Josten, the Chamber’s top lobbyist. “It will be critical to determine how this bill will impact a broad range of industries as well as America’s energy security,” he said.

Associated General Contractors of America criticized the legislation because it would allow the Environmental Protection Agency to continue regulating greenhouse-gas emissions by industries not covered by the new cap-and-trade system.

“By allowing the EPA a virtually free hand to approve or deny construction projects, the bill creates regulatory obstacles that will raise construction costs, delay projects, and stifle demand,” said Stephen Sandherr, CEO of the construction trade association.

The environmental community also was split over the legislation. Environmental Defense Fund president Fred Krupp called the bill “the best opportunity we have ever had to achieve real, meaningful change,” but some environmentalists thought Kerry made too many concessions in his effort to get a bipartisan bill.

“It’s not accurate to call this a climate bill,” said Tyson Slocum, director of Public Citizen’s energy program. “This is nuclear-energy-promoting, oil-drilling-championing, coal-mining-boosting legislation with a weak carbon-pricing mechanism thrown in.”