Democrats say they have been able to peel away suburbanites by emphasizing Republican culpability for the economic decline, a point they say House Republicans helped make themselves by initially balking at the $700 billion bailout and sending the markets into a tailspin that depleted retirement and college savings accounts.

Image Senator Norm Coleman, Republican of Minnesota, faces a tough challenge from Al Franken in his bid for a second term. Credit... Richard Marshall/Pioneer Press, via Associated Press

“Suburban voters are angry that their quality of life and standard of living is under attack,” said Representative Rahm Emanuel of Illinois, chairman of the House Democratic Caucus and a leading advocate of Democrats trying to broaden their appeal in the suburbs.

The partisan spending gap was stark. As of last week, Senate Democrats had spent more than $67 million against Republican candidates, compared with $33.7 million in advertising by Republicans. In the House, the Democratic Congressional Campaign Committee had spent $73 million, compared with just over $20 million for the National Republican Congressional Committee, according to campaign finance reports.

Most of the House Republican money was spent on behalf of incumbents or in districts where a Republican is retiring, emphasizing how much the party was playing defense. By contrast, House Democrats spent most of their money in the last month going after Republican seats in Colorado, Nebraska, Washington, West Virginia and elsewhere. On Sunday, Democrats prepared one last radio advertisement to begin running Monday in an effort to claim the seat of Thomas M. Reynolds, a Republican retiring from his upstate New York district near Buffalo.

“That kind of says it all,” said Representative Thomas M. Davis III, a retiring Virginia Republican whose own suburban seat is likely to go Democratic on Tuesday. Mr. Davis said Republicans simply faced too many disadvantages heading into Election Day, including a higher number of retirements in the House and Senate, an unpopular president and an economic collapse.

“You like to see a fair fight,” said Mr. Davis, a former chairman of the Republican Congressional campaign committee, “but basically we are playing basketball in our street shoes and long pants, and the Democrats have on their uniforms and Chuck Taylors.”