President Barack Obama allowed Republicans to define the terms of the nation's political argument for the past two years and permitted them to draw battle lines the way they wanted. Neither he nor his party can let that happen again.

Democrats would be foolish to turn on themselves in fruitless bickering over whether their troubles owe to a failure to mobilize and excite their base or to win support from the political center. In fact, Democrats held moderate voters while losing independents. What hurt them most was this brute fact: Voters under thirty made up nearly a fifth of the electorate in 2008 but only about a tenth on Tuesday, according to network exit polls. This week's verdict was rendered by a much older and more conservative electorate. Yes, there was an enthusiasm gap.

The end of this campaign thus marked the beginning of the next round, not the end of the contest. Before the next election--which will be decided by a broader electorate--progressives, including Obama, have to be wiser about the fights they pick, more focused on the country's economic pain, and as shrewd as their adversaries have been in promoting debates that rally their troops and advance their goals.

Obama was not wrong to fight for health care, to stimulate the economy when it was in deep peril or to push for financial reform. But by failing to defend these achievements, the president and his allies opened the way for partisan critics who shifted the conversation to airy language about "big government" and "bailouts." One result: Only a third of Tuesday's electorate, according to exit polls, thought the stimulus had made the economy better.

Now Obama needs to offer proposals that promote the common interest and progressive ideals in ways that force Republicans to pay a price for opposing them. The economy still needs more support, and Obama should take up the old Republican idea of revenue sharing to provide states large-scale assistance to prevent layoffs and tax increases. That would be welcomed by the many new Republican governors. Will the party's congressional wing really want to pick a fight with them?

Obama should also push forward with an infrastructure bank, which has bipartisan support. There is no better time to rebuild our nation's crumbling public facilities than when borrowing is cheap. And he should address the decline of American manufacturing, a prime cause of the discontent that roils the Midwest.

To prove that their concern about undisclosed money was not simply a campaign ploy, Democrats should make a full-disclosure law the first order of business in the lame-duck congressional session, and come back to it again and again if the bill is blocked.

Republicans need to be pressed to put specifics behind their antispending, antideficit rhetoric. They should be confronted with budget cuts that force them to face their constituencies. Farm subsidies are not sacred, nor is spending for weapons the Pentagon says it doesn't need, nor are hundreds of millions in tax expenditures and preferences. And if Republicans continue to insist on tax cuts for the wealthy, they should have to identify spending cuts to cover the costs.

On immigration, the president should test the GOP by making plain that no solution is possible absent bipartisan agreement.

The continuing public mistrust of government requires Obama to press on with reforms to the bureaucracy and to the ways the federal government hires people, buys things, and responds to citizens. Government reform should have been a priority his first two years. Now, it's an imperative.

Senate Republican leader Mitch McConnell recently declared that "the single most important thing we want to achieve is for President Obama to be a one-term president." What he said was absolutely true. Republicans and Obama will have to get things done together, but there can now be no expectation of an impossible level of bipartisanship.

Conservatives believe in freedom for the corporate sector, in limiting what the federal government does and in tax cuts for the best-off. Progressives believe in a government that promotes modestly more economic equality, regulates business in the public interest and sees public action as promoting American competitiveness. This election didn't change that. It is a setback for progressives, not a permanent defeat. They took a walloping in the House but held the Senate. The real showdown takes place in two years--and with the electorate equally disapproving of both Republicans and Democrats, that battle is wide open. 

(c) 2010, Washington Post Writers Group

Related: Cash Cowed: How Money Is Deforming Our Politics, by Margaret O'Brien Steinfels