Four moderate Democratic senators — all considered swing votes on climate legislation — want a climate bill put off until next year. They say Congress should focus on passing health-care legislation.

“The problem of doing both of them together is that it becomes too big of a lift,” Sen. Blanche Lincoln (D-Ark.) told Bloomberg.

Sens. Kent Conrad (D-N.D.), Byron Dorgan (D-N.D.), and Ben Nelson (D-Neb.) are also calling for a delay on climate action. While they are amenable to moving ahead with the energy bill that passed out of the Energy and Natural Resources Committee in June, they are less enthusiastic about passing a bill that would cap carbon dioxide emissions.

“We should separate the energy bill from the climate bill,” said Conrad, adding that the energy portion “needs to be done as soon as we can get it done.”

“I see the cap-and-trade being a real problem,” said Lincoln.

But Senate Majority Leader Harry Reid (D-Nev.) does not want to move the climate and energy legislation separately. He has said he plans to combine the energy bill with a cap-and-trade measure that would come from the Environment and Public Works Committee. Sen. Barbara Boxer (D-Calif.), chair of that committee, has said she will introduce her climate bill after the August recess and have it approved by her committee by Sept. 28, the deadline Reid set for committee work on a climate bill.

“I don’t think we are going to take to the Senate floor a bill stripped of climate provisions,” Reid said at an energy summit in Las Vegas last week.

But chances for Senate action on climate this fall are growing dimmer. The health-care debate was pushed off until after Labor Day, when Congress returns from its August recess, and it’s expected to consume much of September and October. Many senators who are playing key roles with health-care legislation are also important to the climate debate, including Finance Committee Chair Max Baucus (D-Mont.), who has said his committee should write the portion of a climate bill that allocates pollution permits. It’s highly unlikely his committee would start work on that until after its work on health care is completed.