Senate Democratic liberals and centrists appeared to be closing in on an agreement tonight on how to configure a public health insurance option, with Senators saying they could finish up by Tuesday evening.

“We’re continuing to work. We’re going to meet at 10 a.m. [Tuesday] and we’d like to get things done by the end of tomorrow if that’s possible,— said Senate Democratic Conference Vice Chairman Charles Schumer (N.Y.), who has been leading the meeting of five moderates and five liberals for several days.

Sen. Tom Harkin (D-Iowa) said the group has been told by Senate Majority Leader Harry Reid (D-Nev.) to finish up by Tuesday night.

“I think all this is going to be decided tomorrow, in fact it has to be decided tomorrow because that’s the deadline we were given,— he said.

But other participants said they were wary of predicting when they might finalize an accord.

“If I said that, I just feel like I’ve jinxed it,— said Sen. Jay Rockefeller (D-W.Va.), a leading liberal in the group.

The rush to reach a deal came primarily from the need to get the proposal to the Congressional Budget Office for an official cost estimate, Rockefeller and others said. But Rockefeller noted that the complexity of the issues and the accelerated timeline has been daunting for the group.

“We have so many things dancing around our heads, we’re like 3-year-olds at Christmas time,— he said after the meeting. “It’s so intense. And we can’t lose [any votes] so the stakes are so high.—

But Sen. Ben Nelson (D-Neb.) said he still has concerns about the policy proposals under discussion. One of those proposals would put the Office of Personnel Management in charge of negotiating with insurance companies that want to sell their plans to small businesses and the uninsured. That plan could be accompanied by an expansion of Medicare that allows some individuals younger than 65 to buy into the government health care program for the elderly. Other options are also under discussion.

“If I seem reluctant it’s because I think others are beginning to see how difficult it is to put together a program on the basis on what you want for government versus what it would require in terms of the technical nature of actuarial science,— Nelson said. “At the end of the day the numbers have to work or somebody is left holding the bag.—

Nelson added, “We’re a long ways away from anything that would even approach being even semi-final, let alone final. I think everybody is anxious to finish as soon as you can. I just don’t know how to put a timetable on it.—