Across the United States, millions of Americans are voting for a new president and members of Congress. Before voting began, major preference polls showed Democrat Barack Obama with a significant national margin over Republican John McCain, both of whom criss-crossed the country, along with their vice presidential running mates, in a final push for more votes. Dan Robinson reports on this and Congressional races.
In the final hours of a hard-fought campaign - the longest and most expensive in American history - Obama and McCain addressed rallies in key states in the East, Midwest and West, attempting to solidify support and win over undecided and independent voters.
Both kept to themes sounded throughout the campaign, including the U.S. economic crisis and the wars in Iraq and Afghanistan - each promising to bring their brand of change to Washington.
Obama, who if he wins will be the first African-American to be president, promised tax cuts for the middle class. McCain campaigned on his Senate record and military experience, pledged to eliminate corruption in Washington and slash government waste.
After stops in Florida and North Carolina, Obama held a final rally in Manassas, Virginia - in a state no Democrat has won since 1964 - addressing tens of thousands of supporters.
"I've just got one question for you, Virginia. Are you fired up? Are you ready to go? Fired up? Ready to go? Fired up? Ready to go? Fired up? Ready to go? Virginia, let's go change the world," said Obama. "Thank you and God Bless the United States of America."
Senator McCain's closing efforts took him to Florida, Tennessee, Pennsylvania, Indiana, Colorado, New Mexico and Nevada, before ending up in his home state of Arizona.
In Indianapolis, Indiana, where some polls showed McCain holding a narrow lead, he asserted to cheering supporters that momentum had shifted his way.
"We've got the momentum," said McCain. "We've the momentum my friends. We've got it!"
Final national polls showed some tightening in the presidential contest, but not sufficient to shift the advantage to Senator McCain. Obama held a comfortable lead in a collection of polls of between five and 11 points.
A final USA Today/Gallup poll gave Obama an 11 point, 53-to-42 percent lead. A NBC/Wall Street Journal sampling put the margin at eight points. Several organizations projected Obama already exceeding 270 electoral votes needed to win, out of a total of 538 electoral votes at stake.
Most polls show Obama with safe leads in Ohio and Pennsylvania, but a much narrower lead in Florida. No U.S. president has been elected without winning two of these crucial states.
McCain campaign officials held out hope for an upset, but analysts call this unlikely, requiring a combination of wins across the country, including states President Bush won in the previous two presidential elections, but where Obama is running strongly.
Joe Biden and Sarah Palin, the Democratic and Republican vice presidential candidates, also kept up a hectic pace.
In Missouri, Biden again linked McCain's economic proposals to President Bush, while Palin rallied supporters in Ohio:
"With Barack Obama as our president we won't be waiting to change our luck, we will change our luck," said Biden. "We will take control and change our luck!
"This is not the time to entrust the powers of the federal government to the one-party rule of Obama, [House Speaker Nancy] Pelosi, and [Senate Majority Leader Harry] Reid!" said Palin.
All 435 seats in the House of Representatives and 35 in the 100 member Senate are up for election, with Democrats poised for significant gains. Republicans are defending 23 of the 35 Senate seats.
Most projections have Democrats expanding their current 36 seat House advantage by at least 20. Potential losses could give Democrats their strongest majority in 18 years, putting Republicans far below their current 199 seat minority.
Democrats would like to widen their current narrow 51-to-49 margin of control in the Senate to or near a 60-seat majority that could make it easier to win votes on legislation.
With early voting in 30 states, more than 40 million Americans - 32 percent of the electorate - may already have cast ballots, and there are predictions of unprecedented voter turnout.
Vote watch organizations have encouraged Americans to report irregularities or attempts at intimidation at the polls.
Polls closing first in Florida, Virginia, Indiana, North Carolina, and Pennsylvania, will deliver early signs of the national trend.
Senator McCain will monitor election results in his home state of Arizona. Senator Obama will be in Chicago, where he started his political career.