Sens. John Kerry (D-Mass.) and Joe Lieberman (ID-Conn.) introduced sweeping climate change legislation Wednesday that faces an uncertain future in the Senate.

But the two former presidential contenders struck an optimistic tone during their high-profile rollout, with Kerry asserting, “This year with this bill we’re going to fight to get 60 votes.”

Kerry noted that the bill includes language adopted last year by the Energy and Natural Resources Committee and a proposal he crafted with Sen. Barbara Boxer (D-Calif.) that was approved by the Environment and Public Works Committee. Four other committees have jurisdiction over the issue, including the Foreign Relations Committee, which Kerry chairs, and shepherding the legislation through those panels will be a delicate, time-consuming process that might keep the bill from getting to the floor this year.

Majority Leader Harry Reid (D-Nev.) “has recognized that he needs to try to pull this together, much as he does with other pieces of legislation,” Kerry told reporters when asked about the outlook of the climate bill.

“Harry is going to pull them together,” Kerry said about the six committees with jurisdiction. “The president has said he wants to move forward on legislation, and I think it’s important we do so.”

President Barack Obama said in a statement, “I look forward to engaging with Senators from both sides of the aisle and ultimately passing a bill this year.”

Liberal Democrats have said offshore drilling provisions in the legislation are a nonstarter, while moderates from manufacturing states want to make sure the bill focuses on clean-coal technology and will not increase utility costs for consumers. Kerry and Lieberman were careful to underscore Wednesday that their bill addresses those concerns.

Still, Lieberman recognized that “this proposal does not cater to the politics of the moment,” as embattled Members focus on their re-election efforts and are gun shy to take a tough vote on another sweeping overhaul measure.

In a statement, Sen. Lindsey Graham (R-S.C.), who abandoned negotiations with Kerry and Lieberman two weeks ago, left an opening to support the measure that included much of the framework the trio had discussed.

“I believe the broad concepts we came up with before are transformational and are the most consumer and business-friendly effort to date in dealing with carbon pollution,” he said. “Most importantly, they can serve as a framework in allowing America to lead in the creation of alternative energy jobs and significantly reducing our dependency on foreign oil. With these goals in mind, I am interested in carefully reviewing the details of the new proposal.”