WASHINGTON — Opposition Republicans scored gains in US elections Tuesday as they appeared set to win the House of Representatives, pick up seats in the Senate and deliver a stinging blow to Barack Obama's presidency.
In the first hours of returns, Republicans won three Senate seats now held by Democrats with victories in Arkansas, North Dakota and Indiana. But Democrats scored an important win by holding their seat in West Virginia in a race that had been considered a toss-up.
That victory, by Gov. Joe Manchin, will make it harder for Republicans to pick up the 10 seats they needed to take control of the 100-seat Senate.
Their prospects were much better in the 435-seat House, where they needed a 40-seat gain. In early returns, Republicans captured 12 seats formerly held by Democrats and opened leads in about 40 others. Democrats had taken only one seat from Republicans, and led for two other Republican seats.
If Republicans take the House, John Boehner would replace Nancy Pelosi as speaker, making him second in line to the presidency after the vice president.
A Republican victory in either chamber would usher in an era of divided government, complicate Obama's ability to enact his proposals during the next two years and possibly force him to fight off attacks on health care legislation and other bills already signed into law.
Although international affairs had little role in the campaign, Obama's global agenda also would be affected in areas such as arms control and climate change.
Obama scheduled a news conference for Wednesday afternoon to discuss the election results. Before the first results came in, Washington already was buzzing with speculation about whether Republican gains would lead to gridlock or attempts to find common ground, and how they would affect Obama's prospects for re-election in 2012.
In addition to the congressional vote, Republicans were expected to make gains in the 37 governors' races and state legislature campaigns, both especially important as states conduct the once-a-decade task of redrawing congressional districts.
The elections were the biggest test yet for the tea party movement, an amorphous series of groups angered by what they see as the excessive growth of government.
The early results offered a mixed picture for the tea party. Rand Paul, son of former presidential candidate Ron Paul, won the Senate seat in Kentucky, despite Democratic claims he was too far out of the political mainstream. Another candidate backed by the movement, Marco Rubio, won in a three-way Senate race in Florida.
The tea party may have prevented Republicans from picking up the Delaware seat long held by Vice President Joe Biden. Christine O'Donnell, a tea party favorite whose outlandish remarks won her national attention, was defeated by Democrat Chris Coons. O'Donnell shocked the political establishment by winning the party nomination from a veteran congressman who had been heavily favored to beat Coons.
The most closely watched race involving the tea party was in Nevada, where Republican Sharron Angle was in a close contest with the top Democrat in the Senate, Harry Reid.
That race, along with Senate contests in Illinois, Colorado, Pennsylvania and Washington state, were seen as toss-ups. Republicans may need to win all those races to take the Senate.
Democrats held onto a seat in Connecticut that once appeared in jeopardy, with state attorney general Richard Blumenthal defeating former wrestling executive Linda McMahon.
A big Republican victory would signal a stunning turnaround in American politics since Obama won the presidency two years ago campaigning on a message of hope and change.
Although the president was not on the ballot, Obama's presidency was at the heart of many campaigns. His popularity has fallen, and Republicans have capitalized on frustration with the weak economic recovery, high unemployment and rising federal deficit.
Four in 10 voters said they are worse off financially than they were two years ago, according to preliminary exit poll results and pre-election polls. Those who cast ballots expressed dissatisfaction with Obama as well as the two political parties.
Democrats blamed the policies of Obama's predecessor, Republican George W. Bush, for the weak economy and said Obama's policies prevented a financial catastrophe. It was difficult to campaign on the message that things could have been worse. Independents and other voters who had supported Democrats in 2008 shifted to Republicans.
"I will honestly say that I voted for him two years ago," said Sally McCabe, of Plymouth, Minnesota. "And I want my vote back."
Obama gave a series of radio interviews pleading with Democratic supporters not to sit on the sidelines. "I know things are still tough out there, but we finally have job growth again," he said in one.
All 435 seats in the House were on the ballot, plus 37 in the Senate.
Besides the gubernatorial and state legislative races, voters were
considering ballot measures in 37 states, including a proposal in
California to legalize recreational marijuana.
Despite the anti-establishment mood, most incumbents were expected to be
re-elected. But 100 House races were seen as competitive, an astonishing
number by American standards. About half those seats were in districts
Republicans lost to Democrats in 2006 and 2008.
Some of the biggest states elected governors, including California,
where Democrat Edmund G. Brown Jr. collided with Meg Whitman in his
attempted return to the office he left more than a quarter-century ago.
In New York, Andrew Cuomo won the office his father held for a dozen