The Senate Finance Committee returns to its mark up today, and for health reform junkies, the number one spectator sport of the moment has become watching committee member Sen. Olympia Snowe’s every move like they were tea leaves to her votes.

Over the course of the debate, Snowe’s support has taken on great importance. It would help the Democratic leadership hold onto their own conservative members and could even pave the way for several more Republican votes in support of reform.  And a series of committee votes on which she has voted with Sen. Baucus has sparked speculation that Snowe is moving toward a yes vote on the overall bill.

For her part, the senior Senator from Maine is keeping her cards close to the vest.  While Snowe’s support would be a political dream-come-true for Senate leadership and the White House, liberals in and out of Congress have less reason to be enthusiastic, since Snowe has been clear that she does not support a public insurance plan except as a fallback in the event that there are not an adequate number of private options.

With the Finance mark-up  slated to wrap this week, we’ll be watching to see how the committee addresses affordability, the public option and employer responsibility – and of course, Sen. Snowe’s votes on these issues and the final bill.

For more, check out the Health Reform Insider.