Sen. Sherrod Brown (D-OH) says he'd likely oppose health care reform legislation if it didn't include a public option--and that he'd have company. "I think a number of Democrats, and I among them, would have great difficulty voting for a bill without a public option," Brown told me today. "I don't want to say absolutely wouldn't. But I would have great difficulty voting for a bill without a public option."

Sen. Bernie Sanders (I-VT) has similarly suggested that he'd oppose legislation without a public option.

Brown co-wrote the public plan provision in the Senate Health, Education, Labor, and Pensions Committee bill with Sen. Sheldon Whitehouse (D-RI)--a temporary member of that panel, who has nonetheless become a vocal proponent of the idea. In his capacity as a surrogate, Whitehouse has insisted that health care legislation include a government insurance option, though he hasn't come as close as his colleagues have to drawing a line in the sand.

As I noted yesterday, the public option's fate--at least in the Senate--rests for now with members of the Finance Committee, which has been riven by disagreement over the idea for months. If they agree to include a public plan in their draft, then the final Senate bill will almost certainly include one as well, and it will either succeed or fail with the overall package. But if they don't, then a fight will be on between public option proponents and those willing to let the provision quietly die.

In the event that the final Senate bill contains a public option, its overall success may depend on the Democratic caucus' ability to unite against Republican filibusters. And on that score, Brown is hopeful. "Senate Democrats have made great progress, in large part because of Harry Reid, in believing that--we're not 100 percent there--that on procedural votes you stick with the party," he says.

This push for party unity on procedural motions has been music to the ears of liberals, who worry that, despite a 60-vote majority, some conservative Democrats might decide to support Republican obstruction efforts. But there's a slim chance that the effort could backfire. If the latter scenario plays out--if Democrats are faced with a reform package that does not contain, or indefinitely delays, a public plan--members like Brown and Sanders may find that they've already foreclosed on their last, best hope for squashing a weak reform package: voting no on cloture.

Assuming that the public option survives the Finance Committee's deliberation's, though, Brown's confident that the Democratic party won't vote against itself. "The public is going to demand it," Brown said. "It's not just Harry Reid talking about it and all of us saying yes to that. I think the public is going to push harder--that every Democratic senator needs to support the party in procedure so that majority can really rule and we really can move forward on health care."