Reid's proposal is similar in many ways to a bill that passed the House of Representatives this month, but it is different in the way it pays for coverage, and it creates a public option.
Both bills seek to remake the way health care is delivered in the United States by instituting new rules for insurance providers, setting up new exchanges to make it easier and more transparent for people without employer insurance to get insurance coverage.
Reid's bill would give states the option of not using the public option. The bill is paid for with new taxes on couples who make more than $250,000 per year and on people, rich or not, who have generous, all-inclusive benefit plans that are valued at more than $8,500 each year.
Sen. Dick Durbin, D-Ill., who is the chief vote counter for Democrats, pledged again Friday to pass a bill through the Senate this year, even if it "could jeopardize Christmas."
But despite the Democratic victory in the procedural vote today, the future of the bill remains murky.
Moderate Democrats have real issues with the bill and leaders have tried to draw a distinction between voting to debate the bill and voting to pass the bill after a floor debate later on.
AARP CEO Addison Barry Rand drew the same distinction in a letter written Friday encouraging Senators to vote to debate the bill without exactly endorsing the full bill.
Moderates like Nelson, Landrieu and Lincoln have not seemed likely to bend in their opposition to the public option. Sen. Joe Lieberman, an independent whose vote Democrats will need, has opposed the public option in Reid's bill.
Liberals like Sen. Roland Burris of Illinois said they won't vote for a bill that doesn't include a public option.
Someone will either have to break their pledge or change their mind for Democrats to pass a bill.
Republicans remain united against Reid's proposal. Democrats could woo support from one Republican -- Maine's Olympia Snowe -- if they made creation of the public option dependent on a trigger, such as affordability benchmarks that private insurers would be given the opportunity to meet. But liberals in the party would revolt.
For now, all Republicans are poised to oppose Reid's bill, which they argue would represent a government takeover of health care. It also relies on nearly half a trillion dollars in cuts to future Medicare spending. Republicans argued the bill should not cut the current government-run programs for seniors.
But the debate turned away from the public option and Medicare Friday, toward the heated national debate on cancer screening and task force recommendations to relax recommendations for both breast and cervical cancer.
Republicans argued those recommendations should be a warning of what would happen under the Democrats' bill.
"At what point is the government going to step in and say, 'We are not paying for that and you are going to die earlier than you would if you had received that treatment,'" said Sen. John Cornyn, R-Texas.
"This is how rationing starts. And that's the point.," said Jon Kyl, R-Ariz.