Retiring Sen. Joseph I. Lieberman said Monday he hopes Congress will complete work on a defense authorization bill before year’s end but added that partisan gridlock could make that goal unattainable.

Lieberman is a senior member of the Senate Armed Services Committee, which is chaired by Michigan Democrat Carl Levin. Sen. John McCain, R-Ariz., is in his final year as the ranking member on the panel before being term-limited out under GOP conference rules. Levin and McCain have sought floor time for the measure (S 3254), but Lieberman signaled Monday that the amendment process remains in flux.

“It sure should get done, and there’s been a lot of pre-conferencing between the House and Senate on the items in both bills,” the Connecticut Independent said in an interview. “There’s now a process by which Sen. Levin [and] Sen. McCain are trying to flesh out amendments that people want to offer because Sen. Reid has made clear this is not going to be an open-ended amendment process because we don’t have the time, but there will be amendments.”

Senate Majority Leader Harry Reid, D-Nev., criticized Republicans on Nov. 14 for not consenting to go to the fiscal 2013 policy bill.

“Probably what we are going to do is move to the bill. I don’t know why in the world we have to file cloture on a motion to proceed to it. I don’t quite understand that. But I haven’t understood that about almost 400 times the last few years. So what we are going to do, and everyone should understand — listen to this, everybody — we are going to move to the bill,” Reid said. “If we get permission to go to the bill, we will have an open amendment process on this bill.”

But Lieberman was not sure that will happen.

“It’s not even for sure that we’re going to go to it when we get back after we finish Sen. Tester’s bill,” he said Monday, referring to a sportsmen’s bill championed by Montana Democratic Sen. Jon Tester that is currently on the floor.

Sen. Rand Paul, R-Ky., held up the defense bill last week, seeking a deal to secure a vote on a contentious amendment about jury trials for Americans detained as part of alleged acts of terrorism.

Without making an agreement with Paul, Reid would have to file a cloture motion to even start the floor debate, which would burn valuable time. Other senators want to offer significant amendments, as well.

For instance, Lieberman highlighted a proposal that he is drafting with New Jersey Democrat Robert Menendez, Illinois Republican Mark S. Kirk and others to impose another round of economic sanctions on Iran.

“What we’re thinking of now is that we would introduce them as an amendment to the Department of Defense authorization bill,” Lieberman said.

Reportedly, that proposal may include restrictions on Iran that would lead to an economic embargo against the country, with exceptions for food, medicine and other humanitarian provisions. The White House would likely oppose that effort, setting up a tough test on the Senate floor.

Lieberman and a separate group of senators are working on sense of the Senate language regarding what he called “the parameters of a possible negotiated agreement with Iran” given that the Obama administration appears to be entertaining a renewed effort at negotiating with the country’s government.

“We think we have an opportunity, responsibility, before the end of this year to talk about what the limits of that are,” Lieberman said.

Emily Cadei contributed to this report.