The Democratic congressional majority grew broader and more muscular in Tuesday’s historic elections, with new members ousting Republicans in the House and Senate and a team of their own heading to the White House.

Senate Democrats edged closer to a supermajority by ousting Republicans in North Carolina and New Hampshire and adding three seats held by retiring GOP incumbents to a fragile 51-49 majority in the Senate. Four other races involving Republican incumbents were too close to call early Wednesday.

In the House, Democrats captured GOP-held seats in the Northeast, South and West, adding at least 15 seats to the 30 they took from Republicans in 2006. With fewer than a dozen races still undecided, they were on a path to pick up as many as 20 seats. Going into Tuesday’s election, Democrats controlled the House 235-199 with one vacancy.

“Tonight, the American people have called for a new direction. They have called for change in America,” House Speaker Nancy Pelosi said.

Senate Majority Leader Harry Reid of Nevada credited the excitement and record turnout that helped propel president-elect Barack Obama to victory.

“Obama ran a terrific campaign, he inspired millions of people,” Reid said in a telephone interview. “It’s been a really good night.”

But even as they celebrated Obama’s election and their own victories, Democratic leaders pivoted to looming issues big and small, from a lame-duck congressional session this month to whether to punish or tolerate a Senate ally who endorsed Republican John McCain. There were bigger questions down the road: how to resolve deep differences in their own ranks over promised reforms like universal health care and energy independence — and just how much the public would punish Democrats if they fail.

However daunting, those were nice problems to have compared with the hangover afflicting Republicans. Before Obama had finished his acceptance speech, GOP lawmakers had turned a harsh eye on themselves.

“We have got to clean up, reform and rebuild the Republican Party before we can ask Americans to trust us again. This must begin with either a change of command at the highest levels or our current leaders must embrace a bold new direction,” Sen. Jim DeMint, R-S.C., said in a statement moments after Obama clinched the election. “Our party must start today to admit our mistakes, fight for our convictions and encourage new conservatives to run for office.”

There were signs of recriminations to come. Rep. Adam Putnam of Florida, the No. 3 Republican, told colleagues in a letter released near midnight that he was stepping down from his leadership post — “reluctantly.”

Not one Republican ousted a Senate Democrat.

But on the brighter side, the GOP blocked a complete rout in that chamber, holding the Kentucky seat of Senate Minority Leader Mitch McConnell and a Mississippi seat once held by Trent Lott — two top Democratic targets. Also surviving was Sen. Susan Collins, R-Maine, who defeated Democratic Rep. Tom Allen by a nearly 3-2 margin despite Obama’s overwhelming victory in her state.

Exit polls showed that voters were deeply anxious about the economy and dissatisfied with President Bush. They haven’t been thrilled by Democrats in Congress, either, largely because the new majority could not agree on how to end the Iraq war as promised.

Exit polling showed that the war remains unpopular, and distaste for the conflict helped Obama. Nearly two-thirds disapprove of the conflict, and that group overwhelmingly backed the Democrat.

But that issue faded this year. Politically, the economy was the number one issue with voters and nothing else came close, exit polls showed. That hurt McCain and trickled down-ballot, hurting some Republican candidates.

Sen. Elizabeth Dole, R-N.C., the former president of the American Red Cross, a one-time presidential hopeful and a household name in Republican circles, lost her seat after only one term to state Sen. Kay Hagan. It probably wasn’t a surprise.

“You’ve got a situation here where the president’s numbers are absolutely, unbelievably poor,” Dole said in a recent interview. “I also think McCain is underperforming right now.” She predicted that would change.

Early Wednesday, the race for North Carolina’s electoral votes was too close to call, but Dole had lost her seat.

In New Hampshire, where McCain beat George W. Bush in the 2000 GOP primary, the self-styled maverick lost to Obama. And incumbent Republican Sen. John Sununu lost to former Gov. Jeanne Shaheen.

Other Democrats who won Republican-held seats were former Virginia Gov. Mark Warner, and cousins Mark Udall of Colorado and Tom Udall of New Mexico.

Those wins bring the Democratic Senate majority to 56, but that number is anything but final. Four races remained without clear winners early Wednesday in Oregon, Alaska, Georgia and Minnesota.

The Democrats’ new majority — for now — includes Connecticut Sen. Joe Lieberman, an independent who has caucused with the party. Many Democrats want to strip him of his chairmanship of the Homeland Security committee, kick him out of the caucus or both because he endorsed his close friend, McCain, over Obama.

Reid said he was meeting with Lieberman later in the week to discuss the matter. Much rides on how badly Democrats need Lieberman to reach the 60-vote threshold required to block Republican filibusters.

In the House, it was the first time in 75 years that Democrats won major gains in back-to-back elections. They gained 30 seats in the 2006 backlash against several Republican scandals.

This year, their wins changed the political geography, regionally. Ousting 22-year veteran Rep. Chris Shays in Connecticut gave Democrats every House seat from New England. Their victory in an open seat on New York’s Staten Island gave them control of all of New York City’s delegation in Washington for the first time in 35 years.

Democrats also rode the coattails of a decisive victory by Obama in New Mexico to win one House seat they haven’t controlled in four decades and another the GOP had held for 28 years. Both were left up for grabs by GOP retirements.

The news wasn’t all good for Democrats. They lost three first-termers in the South, as well as Kansas Rep. Nancy Boyda, whose Topeka-based seat went to Lynn Jenkins, the GOP state treasurer.

Republican attorney Tom Rooney defeated Rep. Tim Mahoney of Florida, who had admitted to two extramarital affairs just weeks before Election Day. Republican Bill Cassidy dealt a bruising defeat to Rep. Don Cazayoux, D-La., elected in a special election six months ago. And in Texas, Republican Pete Olson, a former chief of staff to Sen. John Cornyn, beat Democratic Rep. Nick Lampson.

“We sort of got through this, we think, a little bit better than some people might have expected,” said Rep. Tom Cole of Oklahoma, the head of the Republican House campaign committee. “Our worst days are behind us.”