How will we remember this month, with the recriminations over the failed Christmas bomber, the Massachusetts miracle wrought by Scott Brown, the frightening mid-month dip in the financial markets, the Supreme Court ruling that removed caps on corporate and union spending on political campaigns, the likely death of the massive overhaul of health care, the addition of Sarah Palin to the Fox News palette and the tax breaks and tough talk of the State of the Union?

Will we remember this as the month when Barack Obama's weaknesses were laid bare and his administration came asunder under what the president called in his State of the Union address Wednesday night "the numbing weight of our politics?" Or as the month when the president reinvigorated himself and his team awoke from its slumber?

We won't know for a long time, of course, but while there remain a few breaths in the remarkable month of January 2010 it is not too soon to say that the plate tectonics of politics have shifted.

We know a few things now that we knew but didn't recognize quite so clearly before: President Obama is not infallible nor indestructible. The Democratic congressional leadership is not omniscient nor omnipotent. The language of change is not the Democrats' alone. Populists can come in Republican or Democratic clothes. In a democracy even a super-majority in the Senate cannot force-feed a comprehensive restructuring of something as large as the health care system in a body politic that is not hungry for it.

Politics is taking on new shapes, moving into new means of communication, creating new movements and coalitions, putting new pressures on the elected and the established, bringing new people into the process. As a result there are changes in the language of politics (the new meaning of the phrase "tea party") and in its conduct (Mr. Brown, the new senator from Massachusetts, hardly ever mentioned he was a Republican).

All this may be discomfiting to Team Obama, which a year ago actually thought ObamaCare would be enacted in a carefree progression from Capitol hearings to a White House signing ceremony. But it is a jolt of caffeine to the entire political system, which was in danger of becoming slumberous, or at least stuck in an Obama reverie or, on the right, a fit of Obama resentment. The president's achievement in getting elected was substantial, unmistakably historic. But his election merely gave him a page in history. It did not write anything on it.

Now the political game begins anew. When the Minnesota Vikings and the New Orleans Saints completed four breathless quarters of NFL championship football last Sunday, the referee, Pete Morelli, a high school principal in Stockton, Calif., told the team captains that they were beginning a new game. The score in New Orleans was 28-28. The score in the Senate is 59-41, but it is a new game in Washington nonetheless.

At the heart of this new game are two new forces in American society. One is the president, whom it is important to realize is still a newcomer to national politics. The other is the Tea Party insurgency, which didn't exist when Mr. Obama was first elected, in 2004, to the Senate.

These are new forces but neither is a new type in American politics. America has always loved newcomers, as Abraham Lincoln and Woodrow Wilson demonstrate, and new forms of insurgencies, as the Free Soilers and Populists show, are always springing up in the political landscape. But the collision of a newcomer president and a newcomer insurgency is relatively rare -- and a delicious prospect for those of us who believe, with apologies to the NFL championship spectacular presided over by Mr. Morelli, that politics is the nation's greatest spectator sport.

What makes this a particularly rich moment in American history is that new and powerful pressures are bearing down on both parties.

The Democrats are struggling with a classic clash between the cool reasoning of the pragmatics and the hot desires of the impassioned. Ground Zero is health care, where the pragmatists made all sorts of unseemly deals with senators from the blood-red states of Louisiana and Nebraska but no deals with the deep blue-blooded activists who were told that this, at long last, was their moment. Now it turns out that the pragmatists made deals but got nothing, even as the dreamers are saying that the only trouble with a comprehensive health-care overhaul is that it still has never been attempted in the United States.

But if you think that the angst is only on the left side of American politics, consider what your average Republican lawmaker thinks as he watches Mr. Brown move into the office held as a personal province of the Kennedy family for nearly six decades. Ted Kennedy they understood -- fiery liberal from a liberal state holding a torch for his two martyred brothers. Now there's Scott Brown sitting among them with the smell of tea on his breath but with unpredictable views on abortion and guns. He's no Orrin Hatch, but he's no Olympia Snowe either.

A lot of people sought to claim credit for Mr. Brown's triumph. He calls himself a "Scott Brown Republican," which is a good phrase that will work for about seven more days, because the battle for Mr. Brown's soul is a proxy for a larger battle, for the soul of the Republican Party itself.

Surely I am not the only one who noticed that among those rushing to say he played a pivotal role in the Massachusetts upset was Sen. John Cornyn, who is known in Washington as the chairman of the National Republican Senatorial Committee, but who is known at various tea parties as one of the demons-in-chief, a supporter of the Troubled Asset Relief Program and the very model of what used to be called the Republican regulars.

The regulars want the votes of the tea partiers without the tea baggage. Keep one eye on how that shakes out in primaries in Illinois, Kentucky and Florida. But keep the other eye on the president as he tries to get out in front of all of the people who used to be behind him. Mr. Morelli was right. New game on.

Looking for more from the Post-Gazette? Join PG+, our members-only web site. You'll get exclusive sports content, opinion, financial information, discounts from retailers and restaurants, and more. Our introduction to PG+ gives you all the details.