When Sen. John Kerry began his plea for a climate change bill at a closed-door meeting of his fellow Democrats on Thursday, he started with an apology for being so dogged about getting sweeping legislation done this year.

“I know you feel like this is the only thing I talk to you about,” the Massachusetts Democrat said, according to a person present. But he went on to say how “passionately” he feels about the issue and how this is the right time and year for the party to take on the politically dicey issue.

Kerry was only half-joking about being a broken record when it comes to climate change legislation. His office estimates that over the past year he has had 292 meetings and phone calls with more than 50 Senators, including hourlong talks with 44 Democrats and eight Republicans.

The problem for Kerry is all that work may be for naught if he can’t persuade a handful of Republicans and as many as 10 to 15 fellow Democrats to take a leap of faith on the issue.

“I think it’s hard to get 60 votes on a climate change bill. My sense is it’s easier to get there on just a straight energy bill,” Sen. Mark Pryor (D-Ark.) said of the need for a filibuster-proof vote. “But I appreciate all these Senators working so hard on trying to put legislation together, and I’m committed to at least listen and look at every proposal that is offered. But I think it’s hard to get 60 votes in this environment.”

The proposal by Kerry and his legislative partner, Sen. Joe Lieberman (ID-Conn.), would put a price on greenhouse gas emissions but allow different industries to be subject to different reduction targets.

“Climate change is in trouble for a variety of reasons,” one knowledgeable Senate Democratic aide said. “The proximity of the election is having a majorly negative impact on our ability to get a climate bill through the Senate. The health care bill also scared people, and I’m not sure the oil spill is actually galvanizing people. When people see oil in the water, they don’t think of wind farms. All of those things are a factor.”

Kerry and Lieberman’s ace in the hole — the support of Sen. Lindsey Graham — evaporated as election-year pressures came to bear. In late April, the South Carolina Republican pulled out of talks not because he disagreed with the direction of the bill, but because Majority Leader Harry Reid (D-Nev.) had said he wanted to bring up an immigration bill this year.

Graham said Reid’s decision smacked of election-year politics, while Democrats accused Graham of finding a convenient excuse to extricate himself from an issue his GOP colleagues were not rallying behind.

Kerry has kept up an optimistic view — and his hope that his colleagues will press Reid to take up his measure — but he is largely competing against forces in the caucus that want to sidestep the larger climate debate and do a smaller, energy-only bill sponsored by Energy and Natural Resources Chairman Jeff Bingaman (D-N.M.). Many Democrats also want to respond to the oil spill in the Gulf of Mexico with legislation.

[IMGCAP(1)]”No one pretends this has been an easy issue,” Kerry said in a statement provided by his spokeswoman. “Have I worked aggressively? Absolutely. But I’ve also listened hard. Colleagues have asked me to meet with stakeholders and interests from their states, and I’ve found ways to incorporate their views into our proposal. I’ve asked my closest friends in the environmental community to swallow hard on some pieces that matter enormously to members of our caucus, and I think most senators appreciate that. I believe it’s been worth the effort to fight. … And I’ve always said to my colleagues, I know this is tough, and I know it’s not everyone’s favorite issue, but I only push because I care so much and I desperately want to see us tackle it together as a caucus with one voice rather than giving up.”

Asked Thursday whether he would consider voting for anything less than his bill, Kerry said, “I’m not contemplating anything other right now. I’m working on getting a price on carbon.”

But Kerry may not have helped himself Thursday when he followed his apology with a nearly half-hour lecture to his colleagues on climate change. Sources said the special caucus ended without Senators having the opportunity to ask questions partly because Kerry took so much time. It was a presentation that by most accounts was supposed to take only 10 minutes — a limit that competing presenters such as Bingaman and Sen. Maria Cantwell abided by, according to sources. The Washington state Democrat was presenting her own climate change measure, which boasts support from Sen. Susan Collins (R-Maine).

Reid has scheduled another special caucus this week to continue the discussion.

Another senior Senate Democratic aide suggested the Kerry-Lieberman proposal isn’t gaining traction “because it is being pushed by two of the least-liked members of the caucus.”

Kerry has been a loyal vote for leadership, but his style is sometimes off-putting. Lieberman, on the other hand, has repeatedly made moves — such as campaigning for Sen. John McCain (R-Ariz.) for president and declaring at the 11th hour that he would filibuster a compromise version of the health care reform bill last year — that put him at odds with his Democratic colleagues.

Those issues aside, “I’m not sure Jesus Christ could get a climate change bill through the Senate right now,” another aide said.

Still, Kerry has been getting a good deal of positive news lately. An Environmental Protection Agency analysis of his bill concluded that reducing greenhouse gases 17 percent in the next 10 years was achievable and would not cost consumers thousands of dollars in increased energy bills, as critics have asserted. The EPA said consumers could expect to see costs in the range of $79 to $146 per year.

Kerry and Lieberman also interpreted Obama’s speech last week in which he urged Congress to tackle energy issues in the wake of the Gulf spill as an endorsement of their efforts.

“There can be no doubt that the President is rolling up his sleeves to ensure we establish a market mechanism to tackle carbon pollution, create hundreds of thousands of new jobs each year, strengthen energy independence and improve the quality of the air we breathe,” the two wrote in a statement.

One Kerry aide said the Senator has reason to believe Obama supports his endeavors, given Kerry has had countless private conversations with the president on the issue and was tapped by Reid last year to try to help get the issue into a workable form.

Kerry proceeded to amass an impressive coalition of energy industry and environmental groups behind his approach. Just Thursday, CEOs for Honeywell, General Electric and Dow Corning spoke with Democratic Senators about the need to pass climate change this year, at Kerry’s urging.

“It’s a pretty significant achievement,” another senior Senate Democratic aide said of Kerry’s work on the bill. “But it’s encountering midterm-election-year jitters.”