WASHINGTON — “This is what change looks like,” President Obama said after succeeding where Bill Clinton, Lyndon Johnson and Harry Truman had failed. On Sunday, as comprehensive health care reform was becoming a reality, some people couldn’t bear what they saw.

By early afternoon, a tea party demonstration had assembled on the grounds outside the Capitol and begun its familiar chant, “Kill the bill!” There were the usual placards about socialism, tyranny and the perceived threat to all that is good and true. The movement claims to have African-American and Hispanic followers; maybe it does, but I didn’t see them.

A smaller, more diverse group had gathered nearby to demonstrate in support of the health care legislation. Organizers said they put the rally together overnight to show that rejectionists weren’t the only Americans with strong feelings about the issue.

On Saturday, the vile epithet that is euphemistically called “the N-word” had been hurled at Rep. John Lewis, D-Ga., one of the great heroes of the civil rights movement, as he walked past the tea party crowd. Rep. Emanuel Cleaver, D-Mo., who is also black, was spat upon. Rep. Barney Frank, D-Mass., who is gay, was insulted with the epithet that I guess should be called “the F-word.”

Most Republican opponents of health care reform had the decency — and the political sense — to disavow the racist and homophobic attacks. Incredibly, some did not.

Rep. Devin Nunes of California told C-SPAN: “Yeah, well I think that when you use totalitarian tactics, people, you know, begin to act crazy. I think, you know, there’s people that have every right to say what they want. If they want to smear someone, they can do it.” And Rep. Steve King of Iowa airily dismissed the incident: “I just don’t think it’s anything. … There are a lot of places in this country that I couldn’t walk through. I wouldn’t live to get to the other end of it.”

If the attempt at intimidation had any effect, apparently it was to stiffen Democrats’ resolve. Sunday, after hearing a call to action from Lewis, the Democratic leadership walked that same route arm-in-arm while the tea party demonstrators booed and jeered. House Speaker Nancy Pelosi, striding next to Lewis, carried the oversized gavel that had been used decades earlier to mark final passage of the bill establishing Medicare. Taking literally the advice of Theodore Roosevelt, the first president to call for universal health care, she spoke softly and carried a big stick.

When the House began its final debate, there was already the sense that history was about to be made. On one of her many trips between the House floor and the speaker’s office, Rep. Debbie Wasserman Schultz, D-Fla. — a cancer survivor — said that fighting for health care reform was one of the reasons she ran for Congress. “It’s going to be hard to forget this day,” she said.

When I asked Rep. Bobby Scott, D-Va., to put the vote in perspective, he smiled and said: “Years from now, we’re all going to look back and say that this was one of the days when we were worth a damn.”

Hour by hour, the mood on the Republican side of the aisle — buoyed for most of the day by the tea party hootenanny outside — seemed to deflate.

At the White House there was elation after the final vote. Obama’s much-criticized strategy of pushing forward on health care despite the economic crisis had been rewarded with a historic victory. His tactic of letting Congress shape the legislation had been vindicated. His promise of change had been given new substance.

Even with the “fixes” that now have to be approved by the Senate, the health care bill is something of a mess. But it’s a glorious mess, because it enshrines the principle that all Americans have the right to health care — an extraordinary achievement that will make this a better nation.

It may take years to get the details right. The newly minted reforms are going to need to be reformed or at least fine-tuned, and those will not be easy battles. But the social movements that allowed Obama to become president and Pelosi to become speaker proved that the arc of history bends toward fairness and inclusion.

Needed change must not be thwarted, even if some people find it hard to accept. Obama’s epitaph was right: “We did not fear our future. We shaped it.”

Eugene Robinson’s e-mail address is eugenerobinson(at)washpost.com.