Republicans have recaptured control of the U.S. Senate and expanded their edge in the House of Representatives, giving them a majority in both houses of Congress for the final two years of President Barack Obama's presidency.
Democrats held 55 of the Senate's 100 seats before Tuesday's midterm elections, but Republicans gained at least seven seats with wins in Arkansas, Colorado, Iowa, Montana, North Carolina, South Dakota and West Virginia. Three races were undecided on Wednesday.
Republicans take over U.S. Senate
The results were a stinging rebuff to Obama, who was not on the ballot but said that his policies were. He planned a mid-afternoon news conference to discuss the results and invited congressional leaders to the White House for a Friday meeting to discuss legislative priorities.
A third of the Senate was up for reelection Tuesday, including the Kentucky seat held by Senate Republican Mitch McConnell. He easily defeated his Democratic opponent, Alison Lundergan Grimes, earning a sixth term in office and setting him up to become Senate majority leader in January.
McConnell promised to seek agreement with Obama on some issues. But, at an election night victory party, he also vowed to continue the Republican effort to diminish the size of the national government.
"Friends, this experiment with big government has lasted long enough," he said. "It's time to go in a new direction."
House results, Nov 5, 2014
While taking over Senate control come January, Republicans added at least 13 seats in the 435-member House, where they already held 233 seats.
In Colorado's Senate race, incumbent Democrat Mark Udall was defeated by Republican challenger Cory Gardner.
"Tonight we shook up the Senate. You shook up the Senate," Gardner told supporters. "We go to work to fix a Washington that is out of step, out of touch and out of time."
Senator-elect Cory Gardner, a Colorado congressman, delivers his victory speech in Denver Nov. 4, 2014.
A pledge to rein in the federal government helped propel Republican Senate candidate Joni Ernst to victory in Iowa. She said it was about “getting [federal] spending under control, keeping taxes low, and cutting red tape so businesses can grow and invest.”
Tuesday was not a clean sweep for Republicans, as Democrats held onto Senate seats in states such as New Hampshire, where Jeanne Shaheen won another term in office.
"I will work with anyone in the Senate – Democrat, Republican, Independent – to get things done," she said.
And in Louisiana, incumbent Democratic Senator Mary Landrieu will face Republican Bill Cassidy in a December runoff, since neither won a majority of the votes.
Landrieu challenged her rival to a series of debates on issues including education, jobs and the economy, "Social Security and Medicare, health care, energy and the environment and, yes, international affairs and trade."
Republicans dominate governors' races
Republicans also flexed their muscle in races for governor, even in Illinois, Maryland and Massachusetts – states that dependably have gone for Democrats. As the Associated Press reported, states shoulder responsibility for setting up the insurance exchanges called for in Obama’s health care law, and some have led in raising minimum wages, another of the president’s goals.
Among the winning Republicans were a handful of incumbents who are potential presidential contenders in 2016: New Jersey’s Chris Christie , Ohio’s John Kasich, Michigan’s Rick Snyder and Wisconsin’s Scott Walker.
Among Democrats, New Hampshire’s Maggie Hassan held on to the governor’s seat and Pennsylvania businessman Tom Wolf beat the incumbent, Tom Corbett.
Obama's agenda faces challenge
House Speaker John Boehner said the Republican-controlled Congress will work on energy and jobs legislation, which he said Senate Democrats have been stalling while in control. "It's time for government to start getting results," he said.
With control of Congress, Republicans could raise new disputes with Obama over his signature legislative achievement, health care reform, which has allowed millions of people to secure insurance coverage they could not previously afford. Many Republicans view the law as excessive government involvement, and have repeatedly called for its repeal.
Republicans also have attacked Obama's handling of the Ebola crisis and called for approval of an oil pipeline from Canada through the central U.S., and a curb on government regulation of businesses.
Some opposition lawmakers have disputed the president's handling of Russia's intervention in Ukraine and U.S. airstrikes against Islamic State militants in Iraq and Syria.
The United States' two main political parties also are feuding over spending and tax policies and immigration reform.
Obama had vowed to set new immigration rules by executive order by the end of the year, after the House balked at acting on comprehensive reforms approved by the Senate. Some Republicans already are saying they will seek to block the president from unilaterally changing the country's immigration policies to allow millions of migrants who entered illegally to stay in the United States.
Troubled by political gridlock
Many voters said they are disgusted with political gridlock between Democrats and Republicans in Washington.
"They have to start doing something," Arizona voter Lee Deremo said of congressional politicians, "and I think it just needs to change, plain and simple."
Anger with Washington played heavily in the elections, according to Republican strategist Ford O’Connell: "Two-thirds of America thought the country was going in the wrong direction. They wanted a change in direction. And now it is up to Republicans to bring that change."
Tuesday’s vote was a referendum on Obama’s leadership, according to American University professor Allan Lichtman.
"President Obama dragged down the Democrats," the political historian said via Skype. "It is not as if Republicans in this election represented grand ideas, inspiring solutions to national problems. They were simply pinning every Democrat [candidate] to an unpopular Democratic president."
Reacting to a new political reality in Washington, Obama has invited congressional leaders of both houses and both political parties to the White House Friday.
VOA's Michael Bowman contributed to this report.
WATCH: Related video report by Michael Bowman.
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Republicans Win Control of US Senate in Midterm Elections