In a post-election shakeup, Rep. Nancy Pelosi, a California liberal, is the front-runner in the race to succeed Rep. Richard A. Gephardt (Mo.) as the House Democratic leader, key lawmakers said yesterday.

Pelosi's ascension next week would make her the highest-ranking woman in congressional history and would signal that most House Democrats are ready for leadership that will more aggressively challenge President Bush's agenda -- particularly his tax cuts and foreign policy -- and change the party's direction and face.

Indeed, her race for the post of minority leader against Rep. Martin Frost, a Texas moderate, is shaping up as a broader referendum on the party's future. Frost is warning members that electing a liberal such as Pelosi, who has fought Bush over Iraq and other foreign policy issues, might create a "permanent minority party." But scores of members seem to disagree.

Gephardt, 61, announced yesterday that he will not seek a fifth term as minority leader, the latest casualty of the Republican gains in Tuesday's elections. With Gephardt stepping aside, House Democrats next Thursday will choose new leaders for the 108th Congress, including one of local interest.

Maryland Rep. Steny H. Hoyer has corralled enough support to succeed Pelosi as minority whip, the party's second-ranking House leadership position, House Democrats say. Hoyer, who ran unsuccessfully for the position against Pelosi two years, said he has commitments from 175 members and incoming freshmen. There will be at least 203 Democrats in the 435-member House, with three races undecided.

"Clearly, we have to do a better job, at least of effectively communicating" the party's differences with Bush, said Hoyer. "I don't think there's any sense we need to accommodate Bush if we don't agree with him." He declined to disclose who he will vote for as party leader.

Rep. James P. Moran Jr. of Northern Virginia, a Pelosi backer, said the California lawmaker will have the race wrapped up as early as today, although several members said they want more time to think about their setbacks in the elections before officially picking a leader. The vote is by secret ballot.

While it will be over in one week, the leadership race might become bitter at times, as members seek explanations for Tuesday's election losses. "There's bad blood here and there, but that's how a family is," said Rep. Karen McCarthy (D-Mo.).

Democrats nationwide are confronting a larger dilemma, which is reflected in this contest. If the party appears too liberal, as history has shown, Democrats suffer at the polls. George McGovern in 1972, Walter F. Mondale in 1984, Michael S. Dukakis in 1988 -- and Democrats who ran for other positions in those years -- learned this.

But if Democrats appear too close to Bush and other Republicans, they give voters -- especially their base of union members, minorities, environmentalists and lower-income workers -- little incentive to work or vote for them.

House Democrats, like many party activists outside Washington, are divided over the best approach. Many Democrats think Bush's popularity and the public's desire to rally behind the commander in chief are mostly to blame for their election losses. But they fault their own timidity, too. Many expressed frustration with their party's muddled message heading into Tuesday's elections and their leadership's inability to stitch together a unified agenda for the party.

"We're losing young people," Moran said. "We're disenchanting our base, and I think we're blurring the distinctions between the parties."

House Democrats are dominated by liberals, many from big cities, who want the party to focus on lower-income Americans and the elderly. They want to repeal many of Bush's tax cuts, enacted last year, and to fight for a Medicare prescription drug benefit guaranteed by the federal government. Several members also lament the party's rush toward compromise on economic policy, foreign policy and spending.

"We have to put out a positive agenda, stick with it, and quit chasing around Republicans," said Rep. George Miller (D-Calif.).

Pelosi, who represents San Francisco, draws most of her support from liberals such as Miller. She was one of the most prominent of the lawmakers who opposed last month's resolution granting Bush substantial leeway to go to war with Iraq.

In a statement released late yesterday, Pelosi promised to look beyond ideology and focus on a Democratic agenda that inspires voters and wins elections. "We must draw clear distinctions between our vision of the future and the extreme policies put forward by the Republicans," she said. "We cannot allow Republicans to pretend they share our values and then legislate against those values without consequence."

Frost and many other Democrats worry that Pelosi might pull the party so far to the left that swing voters in middle America will flock to Republicans. Her base is made up of the 30-plus House Democrats from California, who tend to be more liberal than most of the country, and her voting record suggests that Bush would have a harder time striking deals with her than he did with Gephardt.

Even Rep. Anthony D. Weiner (D-N.Y.), who backed Pelosi's leadership bid two years ago, raised concerns that a San Francisco Democrat could be an easy target for the GOP. "We have to be careful not to create a leadership figure that becomes so strident, so confrontational that they become Gingrichian," he said, referring to former House speaker Newt Gingrich (R-Ga.).

Senior Democrats said the only way Pelosi will lose is if a number of southern conservative Democrats threaten to bolt the party if she is elected. So far, none has.

Pelosi hails from a political family in Baltimore, where her father and brother were mayors. An aggressive fundraiser, she ran afoul of campaign finance laws shortly before Tuesday's elections when she created a potentially illegal political action committee to funnel money to colleagues. She was forced to ask several candidates to return her contributions. Members typically see aggressive fundraising as laudable.

Frost -- seen by some Democrats and Republicans alike as a shrewder politician -- is no fundraising slouch himself. He has also won plaudits for overseeing the party's redistricting efforts, which many observers credit with helping limit the party's losses. The party won House seats in two straight elections when he chaired the Democrats' campaign committee in the 1990s.

"He's a unifying person, not a polarizing person, which is what we need right now," said Rep. James L. Oberstar (D-Minn.), a Frost backer.

Frost is campaigning for the job by telling members that he is the only candidate who knows how to keep moderate and conservative Democrats from extinction. "We have to be a big-tent party," he said.

Staff researcher Lucy Shackelford contributed to this report.

Rep. Nancy Pelosi (D-Calif.) Rep. Martin Frost (D-Tex.) Rep. Martin Frost (D-Tex.) announces his bid for the position of House minority leader. He has told party members that he can keep moderate and conservative Democrats from extinction.