Republicans, for example, were counting on wins in Missouri and Indiana. But they ended up all but abandoning their Missouri candidate, Todd Akin, after he remarked in August that women's bodies have ways of avoiding pregnancy in cases of what he called "legitimate rape." In Indiana, Richard Mourdock defeated the more moderate veteran senator Dick Lugar, who would have likely cruised to re-election. Mourdock has come under criticism after saying in a debate that when pregnancy results from rape, it is "something God intended."
Other closely watched races are in Massachusetts, Connecticut, Virginia, Wisconsin, North Dakota, Montana, Nevada and Arizona.
All 435 seats in the House are at stake, but incumbents tend to get re-elected. Democrats seem unlikely to pick up the 25 seats they need to gain control.
The presidential race is so close that calling a winner could be much delayed. Polls are not closed in all 50 states until voting ends in Alaska at 1 a.m. EDT. But in the three states likely to be most pivotal, all votes will have been cast by 8 p.m. EDT. Virginia polls close at 7 p.m. EDT; Ohio at 7:30 p.m. EDT and Florida at 8 p.m. EDT.
Exit polls will show trends soon after polls close, but barring unexpectedly strong showings by one candidate, the vote counts in swing states could take hours — or longer. The 2000 election wasn't decided for weeks because of a dispute over the vote count in Florida. Bush's victory was ultimately determined by a Supreme Court ruling.
Associated Press writer Ron DePasquale contributed to this report.
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