Much has happened in the dense and shifting political landscape of the past 18 months—the quick breakdown along partisan lines in Congress; continuing arguments over spending, the economy and immigration; the big Republican wins in Virginia, New Jersey and Massachusetts; the Gulf oil spill; falling poll numbers for the president and his party.

But the biggest political moment, the one that carried the deepest implications, came exactly one year ago, in July and August of 2009, in the town hall rebellion. Looking back, that was a turning point in both parties' fortunes. That is when the first resistance to Washington's plans on health care became manifest, and it's when a more generalized resistance rose and spread. President Obama and his party in Congress had, during their first months in power, done the one thing they could not afford to do politically, and that was arouse and unite their opposition. The conservative movement and Republican Party had been left fractured and broken by the end of the Bush years. Now, suddenly, they had something to fight against together. Social conservatives hated the social provisions, liberty-minded conservatives the state control, economic conservatives the spending. Health care brought them together. The center, which had gone for Mr. Obama in 2008, joined them.

Neither the Republicans nor the Democrats saw it coming. But it was a seminal moment, and whatever is coming in November, it started there.

It was a largely self-generated uprising, and it was marked, wherever it happened, in San Diego or St. Louis, by certain common elements. The visiting senator or representative, gone home to visit the voters, always seemed shocked at the size of the audience and the depth of his constituents' anger. There was usually a voter making a videotape in the back of the hall. There were almost always spirited speeches from voters. There was never, or not once that I saw, a strong and informed response from the congressman. In one way it was like the Iranian revolution: Most people got the earliest and fullest reports of what was happening on the Internet, through YouTube. Voters would take shaky videos on their cellphones and post them when they got home. Suddenly, over a matter of weeks, you could type in "town hall" and you'd get hundreds, and finally thousands, of choices.

The politicians, every one of them, seemed taken aback—shaken and unprepared. They tried various strategies—mollify the crowd, or try to explain to them how complex governing is. Sen. Arlen Specter tried that in early August 2009, in an appearance with Health and Human Services Secretary Kathleen Sebelius. Faced with fierce criticism of the health-care bill as it then stood, Mr. Specter explained that see here, it's a thousand-page bill and sometimes Congress must make judgements "very fast." The crowd exploded in jeers.

When Rep. Russ Carnahan held a town hall meeting at a community college in Missouri on July 20, he tried patiently to explain that ObamaCare not only would be deficit-neutral, it would save money. They didn't shout him down, they laughed. When Sen. Claire McCaskill appeared before a town-hall meeting in Jefferson County, Mo., on Aug. 11, she responded to the crowd with words that sum up the moment: "I don't get it. . . . I honestly don't get it. . . . You don't trust me?" "No!" the crowd roared.

When Rep. Brian Baird went before his constituents in Clark County, Wash., on Aug. 18, he was met by this speech from a young man in the audience: "I heard you say that you are going to let us keep our health insurance. Well thank you! It's not your right to decide whether I keep my current plan or not, that's my decision." The constituent got cheers.

It was a real pushback, and it was fueled by indignation. The attitude was: "We have terrible worries—unemployment, the cost of government, its demands, our ability to compete and win in the world. You are focused on your thing, but we are focused on these things."

The videos, still on YouTube, can be pretty stirring. There's a real "Mr. Smith Goes to Washington" feel about them. It was not only Democrats but Republicans too who felt the heat, and were surprised by it.

The president, of course, got his victory on health care. But a funny thing is, normally the press and the public judge a president's effectiveness in large part by legislative victories—whether he has "the ability to get his program through Congress." Winning brings winning, which increases popularity. Mr. Obama won on more than health care; he won on the stimulus package and the Detroit bailout. And yet his poll numbers continue to float downward. He is not more loved with victory. To an unusual and maybe unprecedented degree his victories seem like victories for him, and for his party, and for his agenda, but they haven't settled in as broad triumphs that illustrate power and competence.

In the past an LBJ showed his mastery by taming and controlling Congress. Mr. Obama's ability to work closely with the Democrats does not seem like evidence of mastery. The biggest single phrase you hear about him now, and it isn't coming from pundits and being repeated, it is bubbling up from normal people and being seized by pundits, is the idea that he is in over his head, and out of his depth. And this while he keeps winning.

Nor is the left happy with him. In The Nation this week, Eric Alterman writes that most progressives agree "the Obama presidency has been a big disappointment." No public option on health care, and labor unions, "among his most fervent and dedicated foot soldiers," see card check as "deader than Jimmy Hoffa." Is it possible the president "fooled gullible progressives during the election into believing he was a left-liberal partisan when in fact he is much closer to a conservative corporate shill"? Progressives, including two Mr. Alterman knows "who sport Nobel Prizes on their shelves" now feel this way.

Meanwhile some Republicans are feeling triumphalist, but it may be premature. At the moment they are beating up Republican National Committee chairman Michael Steele for his comments on Afghanistan. What was wrong with what Mr. Steele said was obvious: Afghanistan was not Mr. Obama's war of choice but a nine-year-old war the president has so far continued. But Afghanistan, like Iraq, is the meal he was served, not the meal he chose.

Far worse than Mr. Steele's muddling of the facts is that he spoke in a way that suggested the war could be used as a political tool against the administration. He was approaching a grave matter—war—in a merely partisan and political manner. How cheap and hackish.

The Republicans still need to show that they are worthy of the electoral bounty that is likely to come their way. Are they ready to govern, or only to win? Part of being worthy is showing yourself capable of having serious and truly open debate. What, in the post-9/11 world, should be our overarching foreign policy? What is it we're trying to accomplish? How should we try to get it done? What is the way out of our economic disaster? What must we do, how must we do it?

It's hard for those who do politics as a profession not to get lost in the day-to-day, but if they don't start thinking big and encouraging debate, they're going to blow it, too. And they'll find out at a town hall meeting in 2013. Or earlier.