“Tonight we have the opportunity, the historic opportunity to reform health care once and for all,” said Senator Max Baucus, Democrat of Montana, and a chief architect of the legislation. “History is knocking on the door. Let’s open it. Let’s begin the debate.”

The 60-to-39 vote, along party lines, clears the way for weeks of rowdy floor proceedings that will begin after Thanksgiving and last through much of December.

The Senate bill seeks to extend health benefits to roughly 31 million Americans who are now uninsured, at a cost of $848 billion over 10 years.

The House earlier this month approved its health care bill by 220 to 215, with just one Republican voting in favor. That measure is broadly similar to the Senate legislation, but there are some major differences that would have to be resolved before a bill could reach President Obama, and that would almost surely push the process into next year.