Sen. Ben Nelson (D-Neb.) emerged from his office Thursday evening, after a rare day out of sight from the Capitol press corps, apparently no closer to signing on to Senate Majority Leader Harry Reid’s (D-Nev.) health care reform bill.

Nelson, a moderate from a heavily conservative state who is widely viewed as the last Democratic holdout, is holding firm to his opposition to Reid’s $848 billion health care package for several reasons, chief among them the legislation’s lack of stronger language preventing the use of federal funds to pay for abortions.

“Everybody’s looking if there’s a way to achieve some balance here, but it doesn’t look very promising right now,— Nelson told reporters en route to a floor vote. Nelson described the additional problems he has with the bill as equally troubling as the abortion issue.

“They’re serious as well. I know the focus has always been on abortion here, recently. But I’ve raised other serious concerns and those are being addressed as well,— Nelson said. “Some of the things that I’m talking about could be involved in scaling back— the size and scope of the bill.

Earlier Thursday, Nelson announced that he was dissatisfied with compromise abortion language negotiated by Sen. Bob Casey (D-Pa.) and that he remained a “no— vote. An amendment sponsored by Nelson to address the issue failed in a floor vote last week, and Casey, who also opposes abortion, developed the compromise with the goal of attracting Nelson’s vote without alienating abortion-rights Democrats.

Reid is hoping to file cloture on health care legislation as early as Saturday, but Nelson’s opposition could throw a wrench into those plans given that the GOP remains unanimously opposed to the bill and that the Majority Leader is unlikely to move to end the debate on the package without the backing of all 60 Democrats.

Before Nelson can stake out a final position on health care reform, he said he needs to review the legislation’s final cost, which remains unavailable while the Congressional Budget Office analyzes pending changes to Reid’s bill. Nelson also spelled out problems with the package’s proposed tax increases and Medicaid expansion, which he said would be burdensome to Nebraska’s state budget.

Nelson said he would not speculate on whether the changes he wants could be satisfactorily negotiated with leadership and Democratic liberals in time for a final vote to be held before Christmas Day. Nelson said talks with leadership and other Democratic Members are ongoing in an effort to reach a compromise.

“I intend to be home Christmas,— he said.