While the climate change bill is not expected to pass the Senate, the upcoming debate has caused groups from the National Association of Manufacturers to the Sisters of Mercy of the Americas to weigh in on the issue.

Sen. Barbara Boxer (D-Calif.), one of the bill’s main authors, used the Democratic radio address on Saturday to press the case for action.

The legislation, she said, “will not only enable us to avoid the ravages of unchecked global warming, but will create millions of new jobs and put us on the path to energy independence. Other benefits of our legislation will be cleaner air, energy efficiency, relief for consumers and the alternative energy choices that American families deserve.”

Both the breadth of the legislation and the enormity of the potential problems caused by global climate change have attracted the usual suspects in energy and environmental debates, and a number of newcomers as well.

Supporters, in particular, want to demonstrate how their coalition has grown as the scientific consensus that humans are major contributors to the rise in global temperatures has hardened.

On Friday, environmental, development and faith based groups said in a letter to senators that they supported the bill, which has been crafted by Sens. Joseph Lieberman (I-Conn.) and John Warner (R-Va.) and then revised by Boxer, the Environment and Public Works Committee chairwoman.

"Climate change poses one of the greatest challenges to efforts to promote development around the world and reduce global poverty," the groups wrote. Sierra Club, National Wildlife Federation, the Progressive National Baptist Convention and others signed the letter.

It is undeniable that the coalition supporting a so-called "cap and trade" climate bill has grown since Democrats took control of Congress in 2006 and action seemed much more likely. But lobbyists for fossil fuels industries say they are warming to the fight.

With gas prices high and the economy sputtering, manufacturers and other businesses plan to stress how much the bill would cost and how many jobs could be lost.

"We want to let the voters know that there is a price tag to this," said one Republican lobbyist.

In a video sent out on YouTube, Jay Timmons, head of the National Association of Manufacturers lobbying effort, warns that the climate bill could cause "severe damage" to the American economy. The group is encouraging its members to contact Senate offices opposing the bill.

To counteract that criticism, the bill’s authors have added a new safety valve provision to the bill that would make more emissions allowances available earlier to ease a price spike for the credit. The credit would allow the bearer to emit one ton of carbon dioxide, a key greenhouse gas, into the air. The Environmental Protection Agency would give some allowances away to industries for free under the bill. But industries would also have to purchase credits on an open market at some point.

Some labor groups, which have not always seen eye to eye with environmentalists, though they are both key Democratic constituencies, are now on board: "This crucial legislation ... will promote clean-energy infrastructure investments while providing enormous economic opportunity for thousands of highly skilled building and construction trades workers," a letter from the Building and Construction Trades union states.

In addition, a group of investors and pension managers wrote senators two weeks ago in support of the measure. The U.S. Conference of Mayors is also backing the bill.

But even supporters want it tweaked. Some groups want to require steeper emissions reductions earlier, for example, by limiting the number of free allowances given away. Aid groups want more money dedicated to help poor countries adapt to the effects of a changing climate.

It’s all likely too complicated to be worked out in a week or two. But with all three presidential candidates embracing the idea of a cap on greenhouse gas emissions, the Senate debate could very well prove to have been the beginning of action on a long sought climate bill in the United States.