GOP three seats away from Senate majority

Washington (CNN) -- Now, at last, America gets to decide.

Millions of people are casting votes nationwide in an election that could hand Republicans the Senate after a nasty, negative campaign that cost nearly $4 billion.

Voters are encountering some problems as they head to the polls. In Georgia, home to a competitive Senate and governor's race, a state website that provides poll location information was down. Connecticut Gov. Dan Malloy is seeking to extend voting hours after problems were reported at Hartford polling stations.

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Meanwhile, a winter storm in Maine prompted a state of emergency and left 85,000 customers without power on Tuesday morning. Heavy rain is expected in Texas, Oklahoma and Arkansas, where Democratic Sen. Mark Pryor is in a tough battle for re-election.

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Republicans need a net gain of six seats to claim the Senate and polls consistently suggest momentum is moving in their favor. A GOP win would give the party full control of Congress for the first time since George W. Bush was in the White House. Republican dominance on Capitol Hill could quickly transform President Barack Obama into a lame duck, constantly at war with Congress on everything from health care to energy and spending.

And it would set the tone for the 2016 presidential election by pitting the competing priorities of both parties against each other.

'What we are seeing around the country, from one coast to another, is a lot of Republican momentum, a lot of desire for change in Washington,' Republican National Committee Communications Director Sean Spicer told CNN's 'New Day' on Tuesday.

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Spicer's Democratic counterpart, Mo Elleithee, took comfort in the fact that many Senate races, despite being in traditional Republican territory, are still up for grabs.

'A couple of months ago, people thought Republicans were going to run away with this thing in these states, but we are finding them too close to call,' he said.

Republicans sought to turn the election, in which they are also expected to fatten their majority in the House of Representatives, into a referendum on Obama's unpopularity, amid criticism of his handling of crises over Ebola, ISIS and the sluggish economic recovery.

Democrats hammered Republican candidates on local issues and their record on women's health and workplace equality, while branding their foes as oblivious to the struggles of the middle class.

All eyes this evening will be on seats currently held by Democrats that Republicans need

to capture to flip the Senate, including in Iowa, New Hampshire, North Carolina, Arkansas, Colorado and Alaska.

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There could be many tension-packed hours before the fate of the Senate is decided. In Alaska, for example, where Democratic Sen. Mark Begich is in a tight race, polls will not close until 1 AM on the east coast.

Run-off elections, meanwhile, will be needed in Georgia and Louisiana if no candidate gets to the 50% threshold. That means that if things remain tight, the fate of the Senate could be in limbo for weeks.

Final polls in the decisive states showed Republican Joni Ernst in a dead heat in Iowa with Democrat Bruce Braley - although one Des Moines Register survey over the weekend electrified Republicans by putting her up seven points.

In Colorado, which Obama also won twice, Democratic incumbent Sen. Mark Udall is behind after apparently failing to define his GOP opponent, Cory Gardner, as an enemy of young women.

In New Hampshire, Democratic incumbent Jeanne Shaheen is in a dead heat with Republican challenger Scott Brown, and Pryor will lose his Arkansas seat if the polls prove accurate.

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In Kentucky, Mitch McConnell expects to wake up on Wednesday morning as the next leader of the U.S. Senate after a scorched earth re-election race against Democrat Alison Lundergan Grimes.

But Democrats hope to turn the tables on Republicans in Georgia, where Michelle Nunn mounted a strong campaign for a Senate seat that has been in GOP hands since 2002. Still, she hasn't cleared the 50% threshold in polls that would be needed to avoid a runoff.

Sen. Kay Hagan of North Carolina may also be in position to defy her Republican foe after a nail biter of a campaign.

Republicans are also sweating the race in Kansas, where a stumbling re-election bid by Sen. Pat Roberts risks being overtaken by independent Greg Orman. Orman hasn't said which party he would caucus with in Washington and his win could set the GOP back in its bid to win a majority.

'I am not going there to represent the Democratic Party or represent the Republican Party,' he told CNN Tuesday. 'I am going there to represent Kansas.'

Senate races in West Virginia, Montana and South Dakota meanwhile are considered Republican locks.

Even if Republicans win Senate control, they will fall short of the 60 vote supermajority needed to overcome likely Democratic obstruction tactics. But there could be a small window for possible compromise on issues like trade deals and tax reform before the presidential campaign shakes up the political environment.

Some fascinating gubernatorial races will also be decided Tuesday, including in Florida, where former Republican Gov. Charlie Crist is running as a Democrat against Gov. Rick Scott. In Kansas, Gov. Sam Brownback is in danger of losing amid a backlash against his hard core conservatism. Liberal Massachusetts could elect a Republican governor and Ohio's John Kasich is expected to be re-elected ahead of a potential presidential bid.

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The 2016 race effectively gets under way on Wednesday morning and potential candidates mounted marathon midterm campaign swings to road test their messages.

New Jersey Republican Gov. Chris Christie proved his political stamina during the election season while Jeb Bush eased himself back into the spotlight and Rand Paul was everywhere. Wisconsin's Republican governor, Scott Walker, must endure a nerve jangling re-election bid before he can dream of the White House.

For Democrats, Bill and Hillary Clinton threw themselves into the midterm races ahead of her likely 2016 campaign.

But one man was largely absent from the fray -- the president himself.

Obama will watch results tonight from the White House and a Republican triumph

would inevitably be seen as a repudiation of his presidency and pose tough questions for his administration.

The elections are contesting a third of the seats in the 100 member Senate, all 435 seats in the House of Representatives and there are also 36 gubernatorial races on the ballot.

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