WASHINGTON — Steady your nerves, because there is still uncertainty about the outcome of the 2014 midterm elections.
As candidates make their final arguments, 10 races for the Senate are still close enough to hold the key to which party holds power. The possibility of runoffs in Louisiana and Georgia mean it could take weeks before knowing whether the GOP nets the six seats necessary to win the majority.
A dozen races for governor could go either way. Although Republicans are likely to keep control of the House of Representatives, about two dozen seats in play will determine whether the GOP will reach 245 seats — their biggest majority since Harry Truman was president.
Brendan Nyhan, an assistant professor of government at Dartmouth College, warns election watchers to tune out the "noise" Tuesday from exit polls, TV pundits and Internet bloggers. "You just have to wait for the results to come in," he said.
The first polls close at 7 p.m. in a handful of states. Six hours later, the last precinct in the remote Aleutian Islands of Alaska will close.
Here are some states that could provide early clues. All times Eastern.
7:30 p.m. — A Democratic sign
The Senate race in North Carolina between Democratic incumbent Kay Hagan and Republican Thom Tillis could give an early sign of whether President Obama and his party have a good or bad night.
Like many Republicans running for the Senate, Tillis has tried to make this race about Hagan's ties to Obama and Senate Majority Leader Harry Reid.
But Hagan, who is seeking a second term, has kept the race close by stressing her independence and focusing on Tillis' liabilities as speaker of the state's unpopular General Assembly. Libertarian Sean Haugh could draw voters away from both major-party candidates.
"If Tillis wins in North Carolina, that might be a harbinger of a good night for Republicans," said Andrew Taylor, a political science professor at North Carolina State University. "If Hagan wins, the Democrats might hold out some hope that they can hold onto the Senate."
The GOP is heavily favored to pick up three Democratic-held Senate seats and West Virginia will be the first to close. (The others, South Dakota and Montana, close later in the evening.)
8 p.m. — A GOP wave?
Going into the 2006 and 2010 midterms, the political environment was so strong for the party not in power that a wave swept House incumbents out of the majority. If a wave is heading for the Senate this year, it would make itself known in New Hampshire.
The race between Democratic Sen. Jeanne Shaheen, a popular former governor, and former Massachusetts senator Scott Brown has been tightening for several weeks. Brown, a GOP moderate, has overcome initial objections that he is a carpetbagger. Each candidate has tried to brand the other as a party loyalist.
"If Shaheen goes down here that means Democrats across the country are in really, really bad shape," said Andy Smith, director of the University of New Hampshire Survey Center. "That means ... Democrats are getting beat all over the place."
Florida, a perennial swing state in presidential elections, has the potential for all-night nail biting in the governor's race.
Republican Gov. Rick Scott and Democrat Charlie Crist, who is seeking his old job, have been running neck-and-neck. They have sparred bitterly over the economy and education, and both are deeply unpopular with voters. A Quinnipiac Poll released Thursday showed Crist holding an 18-point lead among independent voters, who are critical to his success.
Other states closing at this hour include Massachusetts and Maine, which also have tossup races for governor.
Massachusetts typically bleeds Democratic blue, but has a tradition of supporting moderate Republicans for governor. Republican businessman Charlie Baker, who lost the governor's race to incumbent Deval Patrick four years ago, has opened a lead on Democrat Martha Coakley, the attorney general. If Coakley loses, it would tarnish her reputation because she lost a winnable special election for the U.S. Senate in 2010.
9 p.m. — Double whammies
Colorado, a swing state, features competitive races for Senate and governor. Both major parties could consider the outcome a success.
In the Senate contest, Democratic Sen. Mark Udall faces a tough fight from GOP Rep. Cory Gardner. Recent statewide polling shows Gardner opening a lead, but Democrats are counting on strong turnout to help the incumbent. This is also the Senate race where Latinos could have their biggest impact, since they make up 14.2% of the electorate.
Democratic Gov. John Hickenlooper is essentially tied with Republican Bob Beauprez, a former congressman, in the state's other marquee race.
Kansas, a typically conservative state, features competitive races for Senate and governor. GOP Sen. Pat Roberts is in the fight of his career against independent Greg Orman, who has not said whether he'll caucus with Republicans or Democrats if he wins. An Orman victory would complicate the battle for Senate control.
10 p.m. and beyond — Clearer pictures
By now, a political trend might be coming into focus.
Polls close at 10 p.m. in Iowa and Montana, where GOP Rep. Steve Daines is the favorite. Iowa's Senate race between Republican Joni Ernst and Democrat Bruce Braley is crucial. Both parties are expecting a Dec. 6 runoff in Louisiana between Democratic Sen. Mary Landrieu and Bill Cassidy, the GOP favorite.
The last polling place closes in Alaska at 1 a.m. But the contest between Democratic Sen. Mark Begich and Republican Dan Sullivan may not be decided for a while because it takes time for the votes to come in from the rural parts of the state.
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(Copyright © 2014 USA TODAY)