The U.S. Senate has voted to pass the most ambitious piece of domestic legislation in a generation--a bill that will extend insurance coverage to tens of million Americans, strengthen insurance for many more, and start refashioning American medicine so that it is more efficient.

The vote took place a little after 7 a.m., after brief speeches by the two party leaders, Harry Reid and Mitch McConnell. The final count was a 60 to 39, with every Democrat voting "aye" and every Republican in attendance voting "no."

Vice President Joe Biden presided over the session and, on the floor, members seemed aware of the moment's historical import. The ailing Robert Byrd, who had to be wheeled in to the chamber for each of this week's four votes, reportedly shouted "for my friend Ted Kennedy, aye." Bernie Sanders, the Senate's most liberal member, cast the final vote with a loud, unmistakable "yes." When the voting was over, Democrats broke out into applause.

The party-line outcome was not surprising. But it was clarifying. McConnell used his time to restate some of his party's now-familiar complaints about the measure--and to vow more opposition. "This fight is long from over," McConnell vowed. "My colleagues will work to stop this bill from becoming law."

For all of the recent fighting among liberals, it is not the left that has stood (and still stands) in the way of creating a decent, protective health care system for nearly a hundred years. It’s the right.

First, though, there is more legislating to do. The Senate has a bill, but so does the House. The two chambers must work out their differences--over how to pay for the plan, what level of financial protection to provide, how to design the regulatory infrastructure for making insurance coverage available. With Congress out of session, negotiations are likely to stretch out over a few weeks; both White House and Capitol Hill sources now say it's likely passage will wait until late January or even February.

But, barring the kind of unforeseen political catastrophe not even the determined Republican opposition can concoct, the bill will pass. And it will be, as my colleague Jonathan Chait writes today, a watershed moment.

For nearly a hundred years, the political system has been debating whether access to basic medical care should be a right all citizens enjoy. When reform passes, the political system will finally render its verdict: "yes."