"This option would be available from day one in any state where -- after market and insurance reforms are implemented -- affordable, competitive plans still do not exist," Snowe said in a statement in July, following a meeting with President Obama.
The senator's aides say that alongside her work with the White House, Snowe remains committed to the "Gang of Six" -- a group of three Democrats and three Republicans senators who came together to achieve a bipartisan solution.
"Senator Snowe is committed to finding a bipartisan solution that will increase access to high-quality, affordable health care. Conversations are taking place on her safety-net fallback option as they have throughout the debate this year, as well as other approaches to make certain people have access to affordable options," said Snowe's spokesperson, Julia Wanzco.
"The Senator has had an open line of communication with the White House over the course of the past few months, and looks forward to participating in tomorrow's tele-conference call with the Gang of Six -- as the Senator's foremost goal remains to achieve bipartisan consensus among the six members of the group on a path forward for meaningful health care reform."
While Snowe may be committed to bipartisanship, two GOP members of that group have turned their rhetoric around, creating tensions with the White House. Sen. Mike Enzi, R-Wyo., said last weekend the Democrats' plan would cut choices for Americans and "make our nation's finances sicker without saving you money." Sen. Charles Grassley, R-Iowa, has upped his criticism against the proposed public option plan.
Snowe is likely to gain the support of some other moderate Republicans, such as her colleague from Maine, Sen. Susan Collins. But it looks unlikely that the longtime senator will be able to rally other fellow Republicans on bipartisan consensus if the momentum against public option continues to build.
Most Republicans haven't received any incentives from Democrats and the White House to work towards a bipartisan solution, said Tom Davis, president and chief executive of the Republican Main Street Partnership, a group representing centrist GOP lawmakers. With the midterm election approaching, "for a Republican to do this, they are chopping off an arm and a leg," the former congressman said.
Unlike many of their colleagues, Snowe and Collins hail from a state that's largely Democratic, and they do not face the same pressure from the Republican base as many of their colleagues, which Davis said could play a part in the decision-making process.
"It becomes very difficult for Republicans to meet him [Obama] halfway," Davis said. "The reality is the Republican base at this point is really down on this bill. ... It's a very tough sell."
Her close work with the White House could make Snowe, a respected voice in the Senate, subject of backlash as the debate heats up further.
"I think there will certainly be some backlash from national conservative commentators and we've seen that already at the national level," Brewer said.
In the absence of Sen. Ted Kennedy, who died last week after a battle with cancer, and potentially Sen. Robert Byrd, who has been too sick to attend committee proceedings, Snowe's vote will be important. Democrats will need a Republican senator to get 60 votes if Byrd is missing for a final vote and the Massachusetts' senator seat is not filled by a Democrat.