WASHINGTON — Democrats fell short Tuesday in their drive to win a decisive 60-vote Senate majority that would thwart Republican roadblocks to their legislative agenda.
But their toppling of at least five Republican seats strengthens their hand after two years of often frustrated maneuvering with a slim 51-vote margin.
With returns still being counted in several key Senate contests, Barack Obama's coattails helped unseat at least two Republican incumbents and win three open races where veteran Republican lawmakers were retiring.
Democrats were also making gains in the House, hoping to add 20 seats or more.
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In Senate races, Democrats defeated Republican incumbents Elizabeth Dole in North Carolina and John Sununu in New Hampshire.
In Virginia, Democrat Mark Warner defeated Republican Jim Gilmore in a battle between two former governors. In New Mexico, Democratic Rep. Tom Udall defeated Republican Rep. Steve Pearce.
And in Colorado, Democratic Mark Udall — Tom Udall's cousin — beat Republican Bob Schaffer.
"The days of obstruction are over," said Sen. Charles E. Schumer of New York, chairman of the Democratic Senatorial Campaign Committee, told a celebration party.
There will be no shortage of reasons for the GOP implosion. President Bush's plummeting popularity was a big one. He was virtually absent from the campaign but an albatross for Republicans nonetheless.
From the war in Iraq, which a majority of the public opposes, to the economic crisis, which has been the called worst since the Great Depression, Republicans struggled with how to navigate a political terrain for which they seemed to have no compass.
Obama and the Democrats were more surefooted.
"The Republican playbook that worked for them for a generation, that's become an anachronism," said Simon Rosenberg, president of the New Democrat Network. "There's a new voting population, new coalitions, new issues, new media. The Republicans have been fighting the future. That is one of the reasons why they are in trouble. They've gotten on the wrong side of history."
Their victories give Democrats a 56-seat majority. That includes two independents, Sens. Bernard Sanders of Vermont and Joseph Lieberman of Connecticut, who caucus with them.
Lieberman's future, however, is a question mark. The independent Democrat and the party's 2000 vice-presidential candidate angered Democrats because he supported Republican John McCain for president and criticized Obama.
More Republican incumbents could still fall. But the goal of a 60-vote, filibuster-proof majority looks to be nearly impossible. That's how many votes Democrats would need to sidestep Republican efforts to block their legislative efforts.
To get there, Democrats would have to defeat all the remaining endangered Senate Republicans:
_ Ted Stevens in Alaska, convicted on corruption charges last month
_ Gordon Smith in Oregon, a moderate who linked himself to Obama
_ Norm Coleman in Minnesota, whose race against comedian Al Franken had grown increasingly nasty
_ Saxby Chambliss in Georgia, who was leading his challenger late Tuesday night
In Kentucky, Republicans deflected a strong Democratic effort to unseat Senate Minority Leader Mitch McConnell. He'd been a prime Democratic target.
"Winston Churchill once said that the most exhilarating feeling in life is to be shot at — and missed," McConnell said in a victory speech in Louisville. "After the last few months, I think what he really meant to say is that there's nothing more exhausting."
Otherwise, the night was a disaster for the GOP. It was act two of the downward spiral that began two years ago when they lost control of Congress after 12 years.
The shift put the politics of Capitol Hill in flux. House Blue Dogs, an influential group of fiscally conservative Democrats, will insist that all those Democratic campaign promises be paid for.
Senate Republican moderates will be caught between their tendencies to side with Democrats on issues and loyalty to a shrinking and demoralized party.
Those Republican moderates could become an endangered species in the House. Some prominent examples, such as Rep. Christopher Shays of Connecticut, lost, or were trailing.
"It could very well be a chapter in the unfolding saga of the demise of the moderate liberal Republican," said Michael Franc, vice president of government relations for the Heritage Foundation and a former congressional aide.
Experts said it was unusual to have consecutive national elections when the political shift swings so far in the same direction. Now Republicans are even further in the hole, and a period of recrimination and political bloodletting is sure to follow.
"There will be a sort of purification and cleansing," said Greg Mueller, a conservative Republican strategist. "Tonight was a punishing night for Republicans and a real wakeup call."
Mueller said that Republicans needed to reclaim the issues of fiscal discipline and low taxes.
Dole lost her North Carolina Senate seat to Democratic state Sen. Kay Hagan. The race became increasingly ugly in the final weeks when Dole ran a controversial ad implying that Hagan was "godless."
Hagan criticized Dole during the campaign for being away from the state too often and not paying enough attention to its needs.
"Not many things can dislodge an incumbent with a good name," said Ross Baker, a Senate expert at Rutgers University in New Jersey. "Inattentive, or remote from the state, is a killer."
Former New Hampshire Gov. Jeanne Shaheen knocked off Sununu in a rematch of their 2002 contest. Shaheen linked Sununu to Bush and his unpopular policies.
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