WASHINGTON  Before the anticlimactic demise on Friday of legislation to combat global warming, the Senate majority leader, Harry Reid, Democrat of Nevada, called climate change “the most important issue facing the world today.” Senator George V. Voinovich, Republican of Ohio, a critic of the bill, nonetheless called it “the most significant piece of legislation to ever come out of the Environment and Public Works Committee.”

Senator Barbara Boxer, Democrat of California, said the effort to limit heat-trapping gases was “one of the greatest challenges of our generation.” Senator Barack Obama of Illinois, the presumptive Democratic presidential nominee, said in a statement, “The future of our planet is at stake.”

And even Senator James M. Inhofe, Republican of Oklahoma, the leading opponent of the legislation, called it “probably the largest bill ever considered by the Senate in its impact on the economy and our way of life.”

And so it was, with a chorus of Senate voices having proclaimed the urgency and importance of the issue that the Great Climate Change Debate of 2008 ended on Friday morning, after three and a half days, with a procedural vote that effectively shelved the bill until next year. A motion by Democrats to end debate and move to a final vote, requiring 60 votes to succeed, fell far short, with 48 senators in favor and 36 against.