Yes, we did.

Finally, President Obama can use those words. The passage of health care reform provided the first piece of incontestable evidence that Washington has changed. Congress is, indeed, capable of carrying through fundamental social reform. No longer will the United States be the outlier among wealthy nations in leaving so many of its citizens without basic health coverage. In approving the most sweeping piece of social legislation since the mid-1960s, Democrats proved that they can govern, even under challenging circumstances and in the face of significant internal divisions.

To understand how large a victory this is, consider what defeat would have meant. In light of the president's decision to gamble all of his standing to get this bill passed, its failure would have crippled his presidency. The Democratic Congress would have become a laughingstock, incapable of winning on an issue that has been central to its identity since the days of Harry Truman.

This is why Republicans decided to put everything they had into an effort to defeat the measure. They said its passage would hurt the Democrats in November's elections. They knew that its failure would have haunted Democrats for decades.

Without this concrete achievement, as House Speaker Nancy Pelosi kept warning her troops, Democrats would have been stuck with their votes for reform bills and nothing to show for them. The real and imagined flaws of their proposed system would have been hung around their necks, yet they would have had no way of demonstrating its advantages.

With success comes the chance to defend what is, in many of its particulars, the sort of plan a majority of Americans said they wanted. Yes, it is imperfect and it won't come cheap. But it fills a gaping hole in the American social insurance system. It affords protections that Americans had long hoped for against insurance-company practices that could deny them coverage. It also grants the security of knowing that sickness would not carry the threat of bankruptcy. It will be better still if the Senate enacts the improvements the House has made.

This is also a moment of history, a culmination of the legacies of Truman and Franklin Roosevelt.

On Nov. 19, 1945, Truman stated facts that are true to this day. "People with low or moderate incomes do not get the same medical attention as those with high incomes," he said. "The poor have more sickness, but they get less medical care."

"We should resolve now that the health of this nation is a national concern," Truman added, "that financial barriers in the way of attaining health shall be removed; that the health of all its citizens deserves the help of all the nation." Nearly 65 years later, Truman's wish has come to pass.

It is also worth remembering that when Roosevelt signed the Social Security Act in 1935, he was properly modest. FDR insisted that "we can never insure 100 percent of the population against 100 percent of the hazards and vicissitudes of life." He knew that his bill was more a beginning than an end. The Social Security Act, Roosevelt said, "represents a cornerstone in a structure which is being built but is by no means complete."

That's exactly true of the reform Congress enacted Sunday night. It does not quite cover everyone -- Social Security didn't, either -- and that must be taken care of. There will be years of wrangling over the system's costs and how it works in practice. Every successful health system in the world confronts such arguments. This new law will not end all our health care problems (no law could), but it does a great deal for access, and it makes solving other problems a little easier. Above all, it puts us on a new path.

For Obama, this struggle was transformative. He began his administration full of hope that his campaign pledge to achieve concord across party lines was a realistic possibility. But, when faced with implacable Republican opposition, he jettisoned the happy talk and came out fighting. If bipartisanship is more fashionable than partisanship, partisanship with a purpose is infinitely preferable to paralysis. Obama has made clear that he will reach out when he can, and do battle when he must.

By temperament, the president is more a consensus builder than a warrior. But he is also a practical man who wants to accomplish big things. On Sunday, he did just that on health care, and he earned a place in history.

(c) 2010, Washington Post Writers Group

Related: "Listen to the Sisters" by E. J. Dionne Jr.
"We Can Do Better" by the Editors
"A Modest Miracle" by Charles R. Morris
"America's Blind Spot" by Daniel Callahan