The state is in the first wave to close polling places, at
7 p.m. Washington time. The results will be telling. Obama has
pushed hard to flip the state, which hasn't backed a Democratic
presidential candidate since 1964, and he led in pre-election
polls.

``An Obama win in Virginia would be a sign the race is
over,'' said John Fortier, a research fellow at Washington's
American Enterprise Institute who wrote a book about the U.S.
Electoral College. ``If he wins Virginia, he is likely to be
doing well elsewhere.''

Virginia's results may signal a tidal wave of states
turning Democratic after backing Republican President George W.
Bush in 2004. Another on the watch list at 7 p.m. is Indiana,
which also hasn't backed a Democrat since Lyndon Johnson won in
a nationwide landslide 44 years ago.

Ohio follows Virginia and Indiana with a scheduled poll
closing time of 7:30 p.m. Washington time. In 2004, the state
and its 20 electoral votes remained too close to call until the
next day, when Democrat John Kerry conceded. For McCain, the
state is critical: No Republican has ever won the White House
without claiming Ohio.

Red States Close

North Carolina and West Virginia, two other states Obama is
contesting that went Republican in the last two elections, close
at the same time as Ohio.

Half an hour later, at 8 p.m., the biggest of the
battleground states, Florida, is slated to close all its polls,
along with those in Michigan, Missouri, New Hampshire and
Pennsylvania.

``It is nearly impossible for McCain to win without winning
Ohio, Virginia, and Florida,'' Fortier said. Bush won all three
in 2004, ending up with 286 Electoral College votes. A candidate
needs 270 to get to the White House.

The first poll closings may also offer early clues on
Senate and House races. Kentucky's balloting is due to finish by
7 p.m. and attention will be on Senate Minority Leader Mitch
McConnell's efforts to hold his seat. A loss for the Republican
would bolster Senate Democrats' chances of getting to the 60
seats they need to block a filibuster.

`Important Signal'

McConnell's race will ``be a very important signal,'' said
Rogan Kersh, a public service professor at New York University.
If he loses, ``that likely means a Democratic surge across the
board: a `tsunami election.'''

In the 8 p.m. hour, a major Senate race to watch is in New
Hampshire, where Republican John Sununu is struggling against a
challenge from former Governor Jeanne Shaheen. A Sununu victory
may mean Republicans will be able to limit their losses.

The full picture in the Senate won't be known until after
polls close in Oregon and Alaska, where two Republicans are
defending their seats. In Oregon, where polls close at 11 p.m.,
Senator Gordon Smith is suffering from the voter backlash
against Bush; Alaska Senator Ted Stevens is on the ropes after
being convicted last week for failing to report more than
0,000 in gifts. Alaska's balloting ends at midnight
Washington time.

Democratic chances of adding two dozen or more seats to
their majority in the House of Representatives depend on gains
in populous states such as Florida and Ohio. Results for House
races typically lag behind statewide races for Senate and
president.

Battle for Pennsylvania

The first returns from Pennsylvania, one of the few
Democratic ``blue'' states that McCain actively fought for in
the final days of the campaign will come at 8 p.m. Washington
time. A McCain victory there would be a major boost for the
Republican's chances.

While results in key states such as Virginia and Ohio may
mean the race is all but over, no candidate will have enough
electoral votes to claim victory until 9 p.m. at the earliest.

Obama, 47, an Illinois senator, could surpass 270 at that
time by winning all of the states Kerry claimed and a handful of
the states that backed Bush in 2004 and where he held a pre-
election lead in polls. Among those so-called red states are
Colorado, New Mexico, Nevada, Ohio and Virginia.

McCain, 72, an Arizona senator, would need to win all the
other Bush states from 2004 -- mounting what polls suggest would
be an upset in several of them -- and pick up a vote-rich Kerry
state such as Pennsylvania, or a few of the smaller blue states.

Many states will be too close to call right away. The
Associated Press and television networks use a combination of
data including returns in selected precincts, previous voter
polls and exit polling on Election Day when making their calls.

2000 Debacle

Networks became more cautious after the debacle in 2000,
when they had to retract declarations first that Vice President
Al Gore had won Florida and then that it had fallen into Bush's
column. The AP often holds back a bit longer than the networks;
the newswire never called Florida for Bush in 2000. The state's
vote, and thus the winner of the election, wasn't settled until
more than a month later when the U.S. Supreme Court blocked
further ballot recounts.

Both candidates are assembling squadrons of lawyers in case
the contest for the White House isn't settled on Election Day.
They are being dispatched to monitor voting and be ready to file
challenges over potential fraud or voter intimidation. In
Florida alone, Democrats have assembled almost 5,000 lawyers.

Election officials, meanwhile, are bracing for a huge
turnout, and some states may opt to extend polling hours because
of long lines or ballot problems, delaying election results.

The finale will come in Alaska. While the Stevens
senatorial race will be closely watched, the state shouldn't
play a major role in the presidential campaign. McCain and his
running mate, Alaska Governor Sarah Palin, figure they can count
on those three electoral votes.

To contact the reporter on this story:
Kristin Jensen in Washington at
kjensen@bloomberg.net