(AP) -- Riding a powerful wave of voter discontent, resurgent Republicans captured control of the Senate and tightened their grip on the House Tuesday night in elections certain to complicate President Barack Obama's final two years in office.

Republican Mitch McConnell led the way to a new Senate majority, dispatching Democratic challenger Alison Lundergan Grimes in Kentucky after a $78 million campaign of unrelieved negativity. Voters are "hungry for new leadership. They want a reason to be hopeful," said the man now in line to become majority leader and set the Senate agenda.

Two-term incumbent Mark Pryor of Arkansas was the first Democrat to fall, defeated by freshman Rep. Tom Cotton. Sen. Mark Udall of Colorado was next, defeated by Rep. Cory Gardner. Sen. Kay Hagan also lost, in North Carolina, to Thom Tilllis, the speaker of the state House.

Republicans also picked up seats in Iowa, West Virginia, South Dakota and Montana, where Democrats retired. They had needed a net gain of six seats in all to end a Democratic majority in place since 2006.

With dozens of House races uncalled, Republicans had picked up nine seats in Democratic hands, and given up only one.

A net pickup of 13 would give them more seats in the House than at any time since 1946.

Obama was at the White House as voters remade Congress for the final two years of his tenure -- not to his liking. With lawmakers set to convene next week for a postelection session, he invited the leadership to a meeting on Friday.

A shift in control of the Senate will likely result in a strong GOP assault on budget deficits, additional pressure on Democrats to accept sweeping changes to the health care law that stands as Obama's signal domestic accomplishment and a bid to reduce federal regulations.

Obama's ability to win confirmation for lifetime Supreme Court and other judicial appointments could also suffer.

Speaker John Boehner, in line for a third term as head of the House, said the new Republican-controlled Congress would vote soon in the new year on the "many common-sense jobs and energy bills that passed the Republican-led House in recent years with bipartisan support but were never even brought to a vote by the outgoing Senate majority."

Legislation to approve the Keystone XL pipeline from Canada is likely among them.

There were 36 gubernatorial elections on the ballot, and several incumbents struggled against challengers. Tom Wolf captured the Pennsylvania statehouse for the Democrats, defeating Republican Gov. Tom Corbett. Democratic Gov. Pat Quinn lost in Illinois, Obama's home state.

In a footnote to one of the year's biggest political surprises, college professor Dave Brat was elected to the House from Virginia, several months after he defeated Majority Leader Eric Cantor in a Republican primary.

House Republicans defeated 19-term Democratic Rep. Nick Rahall in West Virginia, beat Rep. John Barrow in Georgia and picked up a seat vacated by a lawmaker in North Carolina.

After years of a sluggish economic recovery and foreign crises aplenty, the voters' mood was sour.

Nearly two-thirds of voters interviewed after casting ballots said the country was seriously on the wrong track. Only about 30 percent said it was generally going in the right direction.

More than four in ten voters disapproved of both Obama and Congress, according to the exit polls conducted for The Associated Press and the television networks.

Still, a majority of those polled supported several positions associated with Democrats or Obama rather than Republicans -- saying immigrants in the country illegally should be able to work, backing U.S. military involvement against Islamic State fighters, and agreeing that climate change is a serious problem.

No matter which party emerged with control of the Senate, a new chapter in divided government was inevitable in a nation marked by profound unease over the future and dissatisfaction with its political leaders.

Several Senate races were close, a list that -- surprisingly -- included Virginia.

There, Democratic Sen. Mark Warner held a narrow lead over former Republican Party chairman and Bush administration official Ed Gillespie.

There was a little good news for Democrats in New Hampshire, where Sen. Jeanne Shaheen was re-elected after a difficult race against former Massachusetts Sen. Scott Brown.

But in Georgia, Michelle Nunn lost to businessman David Perdue, depriving the Democrats of their last best chance to take away a Republican seat. In Kansas, 78-year-old Sen. Pat Roberts fended off a challenge from independent Greg Orman, shutting off another avenue for the Democrats -- their last.

Among the newly elected Republican senators was Rep. Shelley Moore Capito of West Virginia, the first member of her party to win a seat there in more than a half century.

State Sen. Jodi Ernst of Iowa also won, after a campaign that took off when she aired an ad saying she had learned how to castrate hogs as a girl growing up on a ranch.

In statehouse races, Democratic Gov. Andrew Cuomo of New York won a second term.

Former Republican Rep. Asa Hutchinson was elected governor of Arkansas more than a decade after playing a prominent role in President Bill Clinton's impeachment and trial, and Florida Gov. Rick Scott won a tough race for a new term.

Also winning new terms were Ohio Gov. John Kasich, a Republican and potential presidential candidates in 2016.

Another possible White House hopeful, Republican Gov. Scott Walker of Wisconsin, led his rival, Mary Burke.

Not even Democrats claimed a chance to topple the Republican House majority. They spent the campaign's final days dispatching money to districts where incumbents suddenly found themselves in danger.

The elections' $4 billion price tag spending was unprecedented for a non-presidential year