Democratic senators almost universally accept the science behind global warming. Furthermore, the public statements of Senate Democrats that address climate change frequently insist that curbing greenhouse gas emissions requires American leadership. But translating those two beliefs into legislative action continues to elude the Senate Democratic leadership because of the political peril such a bill poses for individual senators.

Since the House of Representatives passed a climate bill half a year ago, momentum in the Senate ebbed in the face of relentlessly bad economic news and then completely stalled as the political cyclone surrounding the health care debate consumed the Senate's attention. Climate legislation seems perpetually "next" on the Senate agenda. First, climate was slated to come after health care. Then it was to follow financial regulatory reform. More recently, Majority Leader Harry Reid (D-NV) acknowledged that consideration would not occur before spring 2010.

This delay is probably quite welcome for Democratic senators from manufacturing states-e.g., Sens. Evan Bayh of Indiana, Sherrod Brown of Ohio, Debbie Stabenow of Michigan, John Rockefeller and Robert Byrd (of West Virginia, Blanche Lincoln and Mark Pryor of Arkansas), Ben Nelson of Nebraska, Bob Casey and Arlen Specter of Pennsylvania and Claire McCaskill of Missouri.

Representing manufacturing states hit hardest by the economic downturn, these senators and their staffs spend much of their time working to promote job growth and revive economic activity. Confronted by challenging economic headwinds, what senator would relish the prospect of debating, negotiating and explaining to an increasingly anxious constituency thorny concepts such as "cap and trade," "carbon offsets," "leakage" or "safety valves?"

While, out of this group, only Bayh, Lincoln and Specter are up for reelection in 2010, Democratic leadership must recognize the political risk climate legislation presents for pro-manufacturing Democrats (Indiana and Arkansas are first and third in percentage of workers engaged in manufacturing!). Any path forward requires these senators to take public votes that force them to choose between constituencies (e.g., utilities vs. the industrial sector), party discipline (e.g., standing with fellow Democrats on procedural votes even in the face of disagreement over substance), and geographic regions (e.g., upper Midwest vs. the Northeast vs. the Southeast).

Further, these manufacturing-state Democrats risk getting caught in the undertow of a public weary of recession, deficit spending and ever bigger government programs. Support for "cap and trade" could easily be turned into an opponent's campaign ad attacking the incumbent for supporting a "cap and tax" program. Industries already weakened by the economy could view climate legislation as the last straw, throw up their hands in the fight to remain globally competitive and off-shore more American jobs.

Even if these Democrats want to show the world and lead by example, a unilateral American effort to reduce greenhouse gas emissions will do little to help the climate if China, India and other rapidly developing nations continue to increase their carbon emissions. The worst situation of all for America and the political fortunes of the senators from manufacturing states would be if America acted alone, and jobs and emissions migrated to the developing world-the result would be worse for our economy and worse for the environment. As McCaskill said in July, "We need to be a leader in the world, but we don't want to be a sucker."

President Barack Obama's decision to go to Copenhagen for the global climate conference is apt to revive climate legislation efforts on the Hill in the near term. Even as Congress completes consideration of health care, works on financial regulatory reform and focuses on a jobs package, committees are likely to work on legislative language and hold numerous hearings related to climate policy.

However, attendance at Copenhagen and any pledge made at the conference, however, will likely not be enough to overcome the dismal state of the economy and the unyielding reality of the 2010 election calendar. For Senate Democrats from manufacturing states, it will be hard to resist the temptation to put off action on climate legislation until after the political wounds surrounding the health care debate heal, Congress acts to address the economy and the state of the manufacturing sector improves.

When economic and political realities eventually permit the Senate to address climate change in a comprehensive fashion, the challenges to these senators will remain. At that point, the path forward for manufacturing-state Democrats must be to ensure that climate legislation preserves the competitive position of American industry. Any climate bill must shield trade-sensitive manufacturers from the higher energy costs that will accompany climate legislation as well as the high compliance costs imposed by the bill. These costs can be addressed through free allowances, limited exemptions and a rigorous border adjustment measure. Brown and others are acutely aware of the damage an unmitigated cap-and-trade program could cause domestic manufacturers and have invested significant time and resources to try and solve this problem.

Climate legislation promises to overhaul the entire energy sector and, in turn, the entire economy. Crafting a bill that meets the needs of manufacturing states will be complicated and demands politically risky votes. Manufacturing-state Democrats hold the key votes for passing or killing climate legislation-in 2010 and beyond-and their concerns must be satisfied before any climate bill can make it through the Senate.