WASHINGTON - The nation may be waiting well beyond Election Day this year to find out who won control of Congress.
It's a troubling ballot-box scenario that has hundreds of lawyers from both parties preparing for battles that could drag on days, weeks or even months past the Nov. 3 dayafter.
Some states don't count substantial amounts of votes until after Election Day. Others require mailin ballots to be postmarked - not received - by Nov. 2, leaving the tally until well afterward. And with polls showing many Republican and Democratic candidates in tight contests, there's plenty of opportunity for confusion, challenges and recounts that could delay the results and ultimately tip the balance of power on Capitol Hill.
A muddled outcome could give rise to yet another kind of election uncertainty. If Republicans emerge from the balloting just short of a Senate majority, their leaders would almost certainly try to prod centrist lawmakers - like Nebraska Democrat Ben Nelson or Connecticut independent Joe Lieberman - to switch and hand them control.
Nelson's staff insists he plans to stay a Democrat.
It's also not entirely clear how a write-in victory by Sen. Lisa Murkowski in Alaska would affect control of the Senate. Republican leaders have abandoned her since her primary loss, so they can't necessarily count on her should she win re-election.
Recent history and this year's political landscape suggest there could be at least one Senate race left up in the air, and as many as a half-dozen or more House races, according to lawyers who specialize in elections and analysts who study them.
Nobody on either side quite knows what will go wrong - but most are pretty sure something will.
"The rule of thumb is that if you think a recount is going to happen in a race, it doesn't, and so what both sides are doing is doing the background work, figuring out what the state law is, getting their computers and background information in place and identifying people who can go in if there's a problem," said Ben Ginsberg, a central figure in the 2000 presidential recount as counsel to George W. Bush's campaign.
"No state thinks it has a problem ... until there's a close race, and you have to open the hood and peer inside."
Alaska has the potential for what one expert called "the perfect storm" of election confusion. It's home to a competitive three-way Senate race in which incumbent Republican Murkowski is running as a write-in candidate against the GOP nominee, tea partier Joe Miller, and Democrat Scott McAdams.
It's also a state that allows absentee ballots to be postmarked right up until Election Day - and where the mail system can be slow - meaning about one-third of votes won't be counted until later. Add in a law that lets officials read ballots according to the "voter intent" - meaning that an incorrectly marked ballot could still be counted if the voter's intent was clear - and it could be a recipe for election disaster.
"Alaska has the real potential for a meltdown," said Paul Gronke, a Reed College professor who studies elections. "If it's close and the Senate's close, wow - then I'm thinking we all better be booking our trips to Anchorage."
The current Senate balance of power is 59-41 in the Democrats' favor, counting the two independents who generally line up with them. With 37 seats in play, a dozen races are close and Republicans need to gain 10 to take control of the chamber. In the House, all 435 seats are on the ballot, and 75 or more are competitive. The GOP needs to gain 40 to win the majority.
"Both parties have brigades of lawyers on standby for possible close races in either the House or the Senate campaigns, and they will start flying out usually the early morning after the election," said attorney Jan Baran, a former counsel for the Republican National Committee.
In the state of Washington, where Democratic Sen. Patty Murray is in a close contest with GOP businessman Dino Rossi, there's great potential for a prolonged vote count. The vast majority of votes there - 85 to 90 percent - are cast by mail, and are required only to be postmarked by Election Day. That means hundreds of thousands might not be counted until two or three weeks later.
Rossi is no stranger to drawn-out vote counts. He lost a 2004 bid to Gov. Chris Gregoire by 133 votes out of 2.8 million cast after a lengthy tally, two recounts and a court challenge. Results weren't final for seven months.
"We know it's agonizing for the campaigns, and we know it's agonizing for the media, but these aren't just ballots that we're sitting on and holding and waiting to count, it's actually ballots that have to be verified for accountability and accuracy," said Dean Logan, the chief election official in Los Angeles County, who held the same job in King County, Wash., the state's largest, during the Gregoire-Rossi dispute.
If a race remains up in the air the day after the polls close, legions of official observers and lawyers from each party descend, and the snapshots that emerge from the votecounting process can be misleading - sometimes showing the eventual loser ahead simply because a new batch of votes has just been opened.
Seven other states - Arkansas, Iowa, Maryland, Massachusetts, New York, North Dakota and Utah - also allow ballots to be postmarked by Election Day, according to a tally assembled by Gronke and his Portland, Ore.-based team, who track early voting and election law changes. Those states feature more than a dozen competitive House races and two for the Senate.
Even in states where the ballots have to be received by Election Day, a substantial number aren't counted until later - because of the added time it takes to process mailed-in votes, provisional ballots given to voters whose names don't appear on the registration rolls, or write-ins.
In California, for example, officials tell the media and candidates to expect that the last count they see on election night will probably be about 80 percent of the votes cast, Logan said. That's usually enough to project a winner - but not in the tightest of contests.
And then there's the possibility of changing sides after the results are final.
A decade ago, Democrats persuaded Sen. Jim Jeffords of Vermont to leave the GOP and vote with them, transforming an evenly divided Senate into one where Democrats had a one-seat majority. That was in May 2001, more than six months after voters went to the polls.
On the other hand, some changes will occur especially quickly this year. Barring unforeseen disputes, winners of special Senate elections in Illinois, Delaware and West Virginia and House races in New York and Indiana are expected to take their seats - and cast their first votes in Congress - within weeks of Election Day. They'll be sworn in for a "lame duck" session to wrap up the year's business before the new Congress convenes Jan. 3.