By Tory Newmyer, CQ-Roll Call

Senior White House Adviser David Axelrod said Sunday that he expects a public insurance option to make it into a final health care overhaul bill despite a promise from one key lawmaker who opposes such a program.

But Sen. Joseph I. Lieberman , I-Conn., who has complicated the fate of that provision by pledging to support a filibuster to end debate on a Senate bill that includes a public option, renewed the threat and defended his position as principled.

The dispute over the public option remains key to the broader debate on health care reform, even as House Democratic leaders last week unveiled a bill featuring the provision and Senate Majority Leader Harry Reid , D-Nev., pledged to include a version of it in his chamber’s measure. The question now centers on whether Reid will be able to gather 60 votes to begin and end debate on that bill to give it an up-or-down vote on the Senate floor.

“I think both the House and the Senate are going to move forward on bills that likely will have a public option,” Axelrod said on CBS’s “Face the Nation.” “The president believes a public option is valuable to create competition within the insurance industry among this group of people who don’t have insurance today, will reduce costs, and it will be a positive thing. So he is eager for that to be in the bill. I think that some version of it will be in the bill.”

Lieberman, an Independent who caucuses with Democrats, repeated his intention to oppose ending debate on a health care bill with a public option. He said the provision has dominated the debate while there is broader bipartisan support for an overhaul package without one. Lieberman’s vow to support a filibuster has riled his colleagues and further complicated Reid’s goal of getting his plan — a public insurance option that states can opt out of — through the chamber this year.

“The public option, I think, was raised in the last year by people who really want to have a government-run health insurance system,” Lieberman said on the CBS program. “That’s their right. I think they’re wrong. But it’s not necessary, as President Obama has said over and over again to achieve the goals he has. So I hope it’s not in there in the end.”

Lieberman said he feels “so strongly about the creation of another government health insurance entitlement ... that I would use my power as a single senator to stop a final vote.”

Lieberman also said doing nothing would be better than approving the establishment of a public option “because I think we have to follow, if I may, the doctor’s oath here in Congress as we deal with health care reform: ‘Do no harm.’ ”

Meanwhile, House Minority Leader John A. Boehner , R-Ohio, said the Democratic overhaul package would “bankrupt America” and challenged the majority to allow a vote on a Republican alternative that he said would be unveiled in the coming weeks.