When President Clinton had his own health-care and spending baggage, he shed it by adopting an agenda that included a balanced budget, frank acknowledgment of the limits of government, welfare reform, and the protection of key social programs such as Medicare and Medicaid. Mr. Clinton would almost certainly have lost the 1996 election had he not taken that approach. Democrats would have suffered major losses in the 1998 midterm election had they not followed him.

Mr. Obama must undertake the same kind of repositioning now in order to turn around his fortunes and those of his party. To be sure, once he’s made the case for conciliation, consensus and fiscal prudence, he can emphasize that the Republicans have failed and are responsible for the debt and the deficit. But he must offer the electorate a choice by making an affirmative case for his administration’s policies.

A negative campaign that focuses on the past and promotes populism is doomed to fail.