After months of negotiations and delays, the Senate finally has a climate bill to debate.

The political climate has changed quite a bit since Sens. John Kerry (D-Mass.), Joseph Lieberman (I-Conn.), and Lindsey Graham (R-S.C.) began work on the legislation, a fact most apparent by Graham's absence at the bill's standing-room-only unveiling Wednesday. And the bill shy of 1,000 pages gives lawmakers a lot to debate.

At the press conference, Kerry and Lieberman framed the American Power Act as a bill that will boost jobs, create revenues to reduce the deficit and taxes, increase America's global competitiveness, and responsibly limit carbon pollution.

"We're caught today in an economic downturn that has left millions of people searching for the next new engine of growth and jobs," Kerry said, flanked by what he called a "never before seen coalition" of business executives, religious leaders, and environmentalists.

Many of those who spoke touted the bill's focus on renewable sources and energy efficiency.

Yet plenty of environmentalists have grievances with the bill. Even the ones who spoke at the press conference called it a starting point.

Though the bill would create the first-ever cap on greenhouse gas emissions, it falls short of the strict restrictions some activists had hoped for and it boosts domestic production of nuclear power and offshore drilling.

Friends of the Earth called the bill dangerous and said it "threatens to stymie [the] fight against global warming."

Kerry, who has a friendly track record on the environment, acknowledged the groups' concerns briefly, saying he had to make "painful concessions" to hash out a compromise that benefits both industry and taxpayers.

The bill enters the political stage at a precarious time. Graham backed out of talks when Democratic leaders indicated that immigration could take precedent over climate change last month. Other lawmakers also inched away from the legislation after the April 20 oil spill off the Gulf Coast made offshore drilling unpopular with both parties.

"It's a very sensitive time," Sen. Frank Lautenberg, a Democrat from New Jersey, said of the bill.

Senate Majority Leader Harry Reid (D-Nev.) hinted the same, saying he won't put the bill up for a floor vote until 60 lawmakers have committed to it. He pledged to "take a look at what we need to do with energy for this year" after the Memorial Day recess that ends June 4.

At Wednesday's conference, Kerry said he had support from Reid and the president. He also offered a warning to those who aren't supporting him: "If Congress can't legislate a solution, the E.P.A. will regulate one. And it will come without the help to America's businesses and consumers that is in this bill."

Offshore drilling remains a cornerstone of the bill. Kerry and Lieberman hope that opening up more spots along the Atlantic coast to drilling will get Republicans and moderate Democrats to agree to the more liberal aspects of the bill, such as renewable energy and emissions caps.

After the oil spill, the senators changed the proposal to let state officials restrict drilling within 75 miles of their coastline. States will still get a 37.5 percent cut of the royalties oil companies must pay the government for use of the land.

It hurts the bill's chances that offshore drilling has become so politically loaded months before midterm elections. It remains to be seen whether the state incentives Kerry and Liebermarn worked into the bill are enough to coax their wary colleagues.

There's no full-scale cap and trade in the plan. As with the House bill (HR 2454 ), the American Power Act caps greenhouse gases. The Senate plans to reduce emissions by 17 percent in the next decade. But the Senate version does away with economy-wide cap and trade, which would have required that companies buy pollution credits from the government and trade them in an outside market.

There were two concerns with that plan, both of which Kerry and Lieberman tried to address.

First, some lawmakers said that monetizing pollution and requiring all companies to clamp down their emissions could burden ailing industries and hurt the economy. So the Senate bill takes an industry approach instead, focusing on the nation's biggest polluters: power plants, large manufacturers, and transportation.

Second, others feared that an outside market for trading pollution credits could be vulnerable to risky speculation and financial collapse. To address that concern, Kerry and Lieberman restricted trading by outside players. Companies that produce transportation fuels will also have to buy pollution permits but won't be able to trade them among themselves.

Even with those provisions, many Republicans are worried that the plan burdens these industries with new taxes and regulations.

Taxpayers and states would get a cut of the revenues. While states get money for allowing offshore drilling, taxpayers benefit from the revenues the government collects from charging polluters. The Kerry-Lieberman plan offers Americans a rebate of two-thirds of all revenues not slated to reduce the federal deficit.

As another nod to struggling Americans, the bill exempts small businesses from greenhouse gas limits.

"This bill only covers about two percent of businesses in America," Kerry said, adding that the subsection is responsible for 75 percent of the nation's greenhouse gas emissions.

To win Republicans over, the bill puts a lot of emphasis on nuclear power. The lawmakers are offering $54 billion in loan guarantees to build nuclear power plants. They also included tax credits for companies that invest in plants or manufacture nuclear parts.

Environmentalists disapprove of this part of the bill, but it may be even more crucial to courting Republican support now that offshore drilling has become a hot-button issue.

It also includes special provisions for certain states. As with most bills, there are certain parts of this one that are meant to placate lawmakers from specific states.

For example, Florida will be allowed to prevent drilling within 125 miles of its coast while other states are limited to 75 miles. That's because Kerry and Lieberman want to keep Sen. Bill Nelson (D-Fla.) from joining Republicans in a filibuster of the bill.

Nelson tweeted them a warning earlier this week that said, "Word is climate bill might let rigs in Florida's no-drill zone. If Sens. Kerry, Lieberman are following me on Twitter: that's a non starter."

The bill also prevents states from having their own cap-and-trade plans, a restriction that will please lawmakers from manufacturing states who are concerned that emissions caps can hurt local businesses.

But it leaves all other state-level emissions standards in place so that California lawmakers don't find their state's strict environmental laws curbed by the national plan.

Kerry and Lieberman also exempted farmers from pollution limits as a nod to rural states.

If all else fails, there are other bills. If the carefully constructed compromise doesn't work out, a smaller bill (S 1462 ) sits in the wings. The bill drafted by Sen Jeff Bingaman (D-N.M.) focuses solely on energy, doing away with the controversial emissions cap.

It boosts domestic renewable energy and increases offshore drilling for natural gas only. Sen. Maria Cantwell (D-Wash.), who has offered up her own separate proposal , said she could support Bingaman's bill if he takes out the drilling.

Kerry and Lieberman emphasized that their bill includes the Bingaman provisions and more. Now it's up to the Senate to decide how much action they want to take on this issue.

Ambreen Ali writes for Congress.org.

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