As Senate Democrats look to close ranks heading into this week’s markup of the Finance Committee health care bill, a perhaps larger political minefield looms — the merger of that measure with a competing Senate plan.

Majority Leader Harry Reid (D-Nev.) plans to reconcile the two bills, forcing Democrats to choose between the nonprofit medical cooperatives proposed by Finance and a public insurance option contained in the Health, Education, Labor and Pensions Committee bill. Moderates tend to favor the co-ops, liberals prefer the public insurance option.

But the merger negotiations — to be held in consultation with each committee and the White House — face even more obstacles, and Democrats are now grappling with how to craft a bill that can earn 60 votes. And Democrats concede they have yet to determine a clear path forward.

“I think it’s going to be a process where the two are combined. But there’s no readily available road map for how that gets done,— said Sen. Bob Casey (D-Pa.), who sits on HELP and favors the public insurance option. “Obviously, Majority Leader Reid will oversee it. But the mechanics of how that gets done are still — I think are still a little unclear.—

Reid will guide the bills’ marriage with strong input from Finance Chairman Max Baucus (D-Mont.) and Sen. Chris Dodd (Conn.), the No. 2 Democrat on HELP. Dodd managed the markup of the HELP bill in the absence of former Chairman Edward Kennedy (D-Mass.), who died of brain cancer in August. Dodd will continue to play a key role in the merger discussions even though Sen. Tom Harkin (D-Iowa) is the panel’s new chairman.

However, Democratic leaders expect President Barack Obama to play the most significant role in shaping the Senate health care bill — and that includes mediating between the Conference’s competing factions.

At least in the Senate, Democrats are looking for Obama to take the lead on the health care reform effort, just as he did during his Sept. 9 address to a joint session of Congress.

“Now that we have a [Finance Committee] mark, at least we have a rough outline of what we’re going to do. It’s not like this is going to start cold,— a Senate Democratic leadership aide said. “We’ll be looking for a significant amount of direction from the president and his staff.—

“It’s going to be a combined effort,— Senate Majority Whip Dick Durbin (D-Ill.) added. “I think that’s the right way to approach it. Every vote is crucial at this point.—

[IMGCAP(1)]Even if Finance finishes its markup by Friday, the merger negotiations would likely not begin until next week at the earliest, given the Senate isn’t in session on Sept. 28 to observe Yom Kippur.

To begin trying to unify Members around a single bill, the Senate Democratic Conference held a closed-door strategy session on Thursday, just before adjourning for the weekend.

In addition to the internal debate over the public insurance option, Democrats are at odds — or at least in mild disagreement — over several issues.

Democratic centrists, particularly concerned about the federal deficit and the overall health care reform price tag, have taken issue with the expensive and expansive HELP bill. Democratic liberals, more focused on expanding coverage to the uninsured and underinsured, don’t believe the Finance legislation goes far enough to provide quality care and access to it.

Harkin cautioned that the bill that comes of the Finance and HELP merger is not guaranteed to be the final Senate product. Harkin said Senators unhappy with the legislation are likely to offer amendments on the floor that could substantially alter what eventually clears the Senate, with further changes possible in a conference committee with the House.

“There’s a lot of steps ahead,— Harkin said.

Given the Republicans’ solid opposition to both the Finance and HELP bills, the Democrats are unlikely to get much help from the other side of the aisle as they try to cobble together 60 votes for health care reform. At this point, the only Republicans whom Democrats may persuade to come on board are Sen. Olympia Snowe (Maine) and possibly Sen. Susan Collins (Maine).

The looming HELP/Finance merger was a concern for the three Republicans who attempted to negotiate a bipartisan Finance bill in the now-defunct gang of six Senators. Finance ranking member Chuck Grassley (R-Iowa), Sen. Mike Enzi (R-Wyo.) and Snowe repeatedly expressed concerns that any deal they might reach with Baucus and Democratic Sens. Jeff Bingaman (N.M.) and Kent Conrad (N.D.) would be nullified in a merger with the more liberal HELP bill.

Republicans often cited the merger as a reason they were reluctant to support any bipartisan bill that might emerge from Finance. Grassley said he could never get a commitment from Obama or the Democratic leadership that any Finance measure would not ultimately be “obliterated— in the marriage.

“That endgame was as important as the product,— Grassley said, “not only to Sen. Snowe, Enzi and me. It was very, very important to a lot of people in our caucus that would have liked to have seen a bill.—