A decade after Bill Clinton pushed his party toward the center of American politics, inspiring a vibrant movement of "New Democrat" followers in Congress, a liberal resurgence is sweeping the party, threatening to brush centrists to the side.

Democrats today are expected to elect Rep. Nancy Pelosi, a liberal from San Francisco, as minority leader and two East Coast Democrats to lead the party in the 108th Congress. There's little doubt that on issues of trade, gun control and tax cuts, House Democrats are about to take a left turn.

At the national level, Al Gore, who has struck a markedly more liberal and populist tone than the one he set as Clinton's vice president; Vermont Gov. Howard Dean, who's pressing for a nationalized health care system; and Sen. John F. Kerry, from the liberal bastion of Massachusetts, are rallying the party's disgruntled base, in large part with old-school populism.

Two years after leaving office, Clinton, still scarred by scandal, isn't in a strong position to defend his New Democrat legacy. Sen. Joseph I. Lieberman (D-Conn.), Gore's running mate in 2000, is the only prominent presidential hopeful proudly carrying the centrist banner -- and he says he won't run if Gore does.

But most troubling to some in the centrist movement, the incoming House Democratic leadership is deeply rooted in the liberal hotbeds of the two coasts. This could spell trouble for Democrats in the years ahead. If the party moves too far left, political observers say, it could alienate swing voters and complicate its efforts to win back the presidency and control of Congress in 2004.

Party leaders are "going to have to figure out how to get people from the center of the country and center of the party to be part of what they are doing," said Rep. Martin Frost (Tex.), whose unsuccessful bid to become minority leader drew support from centrists who fear Pelosi might pull the party in the wrong direction. "That's their challenge, and it remains to be seen if they can meet it."

When Frost dropped out of the race last week, conceding defeat, New Democrat Harold E. Ford Jr. (Tenn.) picked up the centrist flag. Several centrists are lining up behind him.

"Democrats can't win by merely rallying the faithful," said Rep. Charles W. Stenholm (Tex.), a founder of the "Blue Dogs," the fiscally conservative Democrats from swing districts, mostly in the South. At a news conference yesterday in which he and a dozen other Blue Dogs endorsed Ford, Stenholm rattled off nine House races in which Democrats won reelection this year by 10,000 votes or fewer. "These candidates need to attract independent and some Republican voters in order to win," he said.

Rep. Marcy Kaptur (D-Ohio) jumped into the race yesterday, sounding like a referee between the competing factions. "We should not be talking about left or right or center," she said. "We need to be talking about the reform agenda."

While liberals are seizing the moment in the wake of the elections, many Democrats see their ideology as recipe for failure in the future.

"Pelosi, who's not a part of the New Democrat movement, if she wants to become speaker, will have to lead . . . the New Democrat way," says Al From, founder of the centrist Democratic Leadership Council. "We have not been able to win with the old message of prescription drugs and never touching Social Security."

Pelosi yesterday moved aggressively to placate New Democrats by naming one of their own, Rep. John M. Spratt Jr. of South Carolina, as her top assistant (the No. 5 leadership post) and later speaking at a dinner sponsored by the New Democrat Network, which raises money for centrist candidates. Some Democrats are pushing her to name Frost chairman of the Democratic Congressional Campaign Committee.

While several centrists back her publicly, many fear her privately. This year, Pelosi has voted against tax cuts, trade bills and the resolution authorizing Bush to use force in Iraq, all of which most moderates backed.

If Democratic leaders "run left at all from where we are right now, we won't be competitive at all" in the 2004 presidential and congressional elections, said Simon Rosenberg of the New Democrat Network. Many centrists agree with him.

As Clinton showed in winning two terms as president, Democrats need to draw the support of independent voters throughout the country. They are the soccer moms of suburbs and business owners in small towns, not aligned with either major party. In a nation split almost 50-50 between the two parties, these are the up-for-grab voters who decide national, state and local elections.

In this year's elections, several gubernatorial candidates who ran as New Democrats won, most notably Bill Richardson in New Mexico and Kathleen Sebelius of Kansas. Many state and local candidates found similar success.

Nonetheless, as Democrats sift through the wreckage of last week's elections, many fault party leaders for rushing too quickly to the center and failing to excite the party's base of abortion rights supporters, environmentalists, minorities and union members. But as more exit polls come to light, it appears that Democrats lost several key elections by failing to attract swing voters, particularly in the "red" states Bush carried in 2000.

In 2004, Democrats expect to do well again in California, New York and other liberal-leaning states. But it's the states in between that will decide who wins the presidency and controls the House and Senate.

Nevertheless, the dearth of support for Frost and now Ford in their bids for the House leadership post shows the strong grip liberals have on the party, especially at the congressional level.

Rep. Steny H. Hoyer (Md.), a self-described "progressive" with stronger ties to centrists than Pelosi has, enjoys enough support to become minority whip, the party's second-in-command. The too-close-to-call race for caucus chairman pits two liberal Democrats: Reps. Robert Menendez (N.J.) and Rosa L. DeLauro (Conn.). The fourth-ranking job of caucus vice chair will go to one of three liberals: Rep. Zoe Lofgren (Calif.), Gregory Meeks (N.Y.) or James E. Clyburn (S.C.).

Senate Democrats yesterday reelected two left-of-center leaders: Thomas A. Daschle (S.D.) as minority leader and Harry M. Reid (Nev.) as minority whip.

Rep. Nancy Pelosi (Calif.) in her office with supporters, including Rep. James P. Moran Jr. (Va.), far right. Pelosi is expected to be chosen as House minority leader, a move seen as evidence of a shift to the left in Congress.