The Senate could take up its health care reform bill as soon as the week of Columbus Day, but uncertainties about when it will be ready for prime time could push that tentative timeline back, aides said late last week.

Finance Chairman Max Baucus (D-Mont.) is shooting to complete his markup of the legislation by Thursday or Friday, senior Senate Democratic aides said. Majority Leader Harry Reid (D-Nev.) has said he will huddle for several days with the White House, Baucus, and Sen. Chris Dodd (D-Conn.) to marry the Finance package with a bill that Dodd shepherded through the Health, Education, Labor and Pensions Committee in July. Dodd was filling in for the late Chairman Edward Kennedy (D-Mass.).

The merged measure could come up the week of Oct. 12, aides said of the most optimistic timeline. Reid has repeatedly suggested the Senate could take that week off for a recess, but the health care reform debate would likely take precedence.

“If the bill’s ready at that time and if we need to work through that week, of course we will do so,— said one senior aide.

The biggest uncertainty involves how fast the Congressional Budget Office can score the budgetary effect of the bill.

“By the time we take the bill to the floor, everyone will have a clear understanding of the budgetary and fiscal impacts of this bill,— the senior aide vowed.

Reid has yet to make a decision on how to deal with one of the most vexing issues facing his Caucus — whether to bring up a bill with a public insurance option, as most of his Members would prefer, or to explore other alternatives backed by Democratic centrists. Reid has said he personally prefers the public option, but he has not ruled out bringing up a measure, such as the current Finance plan, that would create nonprofit health care cooperatives.

To secure the vote of at least one Republican — Sen. Olympia Snowe (Maine) — Reid could also decide to go with a “trigger— for the creation of a public option as a fallback if private insurers do not reduce costs and increase coverage on their own. The White House has expressed openness to that approach, if it would convince Snowe to support the overall measure.

The second week of the Finance markup could help to settle some of that debate for Reid, as the panel plods through dozens more amendments. For example, the committee will likely vote on the public option Tuesday.

Democrats are also expected to try to tackle provisions in the bill they say could unfairly penalize middle-class Americans who do not buy insurance under a new mandate that all citizens carry health insurance.

This week is likely to feature long days and nights in the committee, just as the first week did, as Republicans continue to push numerous amendments and Democrats accuse them of trying to slow-walk the bill.

Still, both sides found something to like about the first week of markup — including the Republicans, who generally saw their amendments defeated along party lines.

Sen. Mike Enzi (R-Wyo.), a Finance member who also serves as ranking member on the HELP Committee, said his GOP colleagues made a conscious decision to approach this markup differently than the amendment process for the health care reform legislation that passed out of HELP in July.

Enzi said the GOP made the mistake in that markup of offering a comprehensive alternative to the Democratic bill. After about two hours of debate, the proposal went down to defeat, with many of the specific counterarguments the Republicans wanted to make getting glossed over.

In the Finance markup, however, the Republicans have chosen to offer narrowly focused amendments, as opposed to a broad counterproposal to the Baucus bill, ensuring that each point the GOP wants to make gets a hearing, albeit one that has ended in defeat. Enzi said Democratic charges that the Republicans are taking pot shots at the bill simply to score political points “really irritates me.—

“We have the comprehensive plans. In the HELP Committee we made the mistake of offering the comprehensive plan. We probably got about two hours to debate it,— Enzi said Friday. “So, you get cut out of the debate. They just have to nit-pick a couple of provisions in a 1,000-page bill, and everybody votes against it based on those two provisions. That’s not fair, so what we’ve decided to do is do the real issues and do them one at a time.—

Democrats take a different view.

Senate Democratic Conference Vice Chairman Charles Schumer (N.Y.) said the Republicans’ failure to produce a comprehensive alternative to the $900 billion package introduced by Baucus is evidence of their blatantly political approach to the health care reform effort.

Democrats were clearly irked last week with several Republican amendments, including one to require full legislative language and a final CBO cost estimate before a vote to report the Finance bill out of committee could be held.

“The fact that they don’t have a plan; almost all of their amendments are scoring political points, as opposed to actually getting something done to make people’s health care better is going to come through very strongly as it accumulates,— Schumer said, following the conclusion of Friday’s markup session. “People want action. They may not agree 100 percent with what you’re doing. But if you seem to be simply saying no, or scoring political points, you’re not going to win.—