[T]he truth that liberals and Obama must grapple with is that they have failed so far to dent the right's narrative, especially among those moderates and independents with no strong commitments to either side in this fight.

The president's supporters comfort themselves that Obama's numbers will improve as the economy gets better. This is a form of intellectual complacency. Ronald Reagan's numbers went down during a slump, too. But even when he was in the doldrums, Reagan was laying the groundwork for a critique of liberalism that held sway in American politics long after he left office.

Progressives will never reach their own Morning in America unless they use the Gipper's method to offer their own critique of the conservatism he helped make dominant. It is still more powerful in our politics, as we are learning in Massachusetts, than it ought to be

There are at least three keys to understanding Obama's approach to (and avoidance of) ideology. There is, first, his simple joy in testing himself against those who disagree with him. Someone who knows the president-elect well says that he likes talking with philosophical adversaries more than with allies.

This part of him was once the detached writer and professor who could view even his own life from a distance and with a degree of abstraction. Seen with perspective, after all, the ideological differences in the United States are rather small. We have no major socialist party, and when it comes down to it, even conservatives are reluctant to dismantle our limited social insurance and welfare programs.

But Obama's anti-ideological turn is also a functional one for a progressive, at least for now. Since Ronald Reagan, ideology has been the terrain of the right. Many of the programs that conservatives have pushed have been based more on faith in their worldview than on empirical tests. How else could conservatives claim that cutting taxes would actually increase government revenue, or that trickle-down economic approaches were working when the evidence of middle-class incomes said otherwise?

Obama's anti-ideological talk is not just a vehicle for progressive inclinations but the real deal. Obama regularly offers three telltale notions that will define his presidency -- if events allow him to define it himself: "sacrifice," "grand bargain" and "sustainability."

To listen to Obama and his budget director Peter Orszag is to hear a tale of long-term fiscal woe. The government may have to spend and cut taxes in a big way now, but in the long run, the federal budget is unsustainable.

That's where sacrifice kicks in. There will be signs of it in Obama's first budget, in his efforts to contain health-care costs and, down the road, in his call for entitlement reform and limits on carbon emissions. His camp is selling the idea that if he wants authority for new initiatives and new spending, Obama will have to prove his willingness to cut some programs and reform others.