The candidates have spent almost two years staking their positions on a broad swath of issues, but in the lead-up to Election Day, voters said the economy trumped everything
Obama retained an overall lead in the most recent ABC News/Washington Post poll, 54 percent to 43 percent, among likely voters interviewed Wednesday through Saturday.
The candidates' identities, as much as where they stand on issues, have been a mainstay of the campaign. McCain, a bona fide war hero and long-serving lawmaker, would be the oldest first-term president if elected. Obama, a virtually unknown Illinois junior senator when he announced his candidacy, will be the first black president if he wins.
Since Obama was pitted against former first lady Sen. Hillary Clinton of New York during the Democratic primaries, America's best principles and worst prejudices have been confronted and debated.
Sexism became an issue, first when Clinton argued that sexist treatment in the media and electorate had scuttled her chances at the nomination, and more recently when Palin complained that focus on her $150,000 GOP-bought wardrobe would not have been an issue if she were a man.
McCain goes into today's voting a decided underdog trailing in the polls. But with a flailing economy and an unpopular Republican president, some have argued that the deck is stacked against him, or any Republican nominee.
"People are looking for great meaning and significance in this election. Given the state of economy, I don't think it's a surprise that Obama is leading," said ABC News political consultant Torie Clarke, a former assistant secretary of defense during the first term of the Bush administration.
Obama did more than just tap into growing feelings of resentment. He offered a candidacy centered around hope and optimism, and, in perhaps the greatest and most calculated flip-flop of his campaign, forwent public financing allowing him to raise hundreds of millions of dollars from donors contributing small amounts of money.
McCain too changed course. In the final weeks of the campaign, the Arizona senator struck a more negative tone and along with Palin began attacking Obama on his relationships and judgment.
In the third and final presidential debate, McCain assailed Obama for his relationship with 1960s radical William Ayers and his campaign began aggressively using auto-dialed calls to voters, known as "robocalls," to relay negative messages, frequently focusing on the Democrat's experience and readiness for the White House.
That strategy didn't seem to achieve the desired effect, with voters responding in polls in the race's final weeks that they were turned off by the negative ads and attack tactics.
Obama has in recent weeks consistently led in national polls and the electoral math as it stands clearly favors him. Buoyed by newly registered voters, blacks and young people, Obama has found support even in states once considered Republican strongholds. But things are far from absolute and both supporters and opponents of Obama note that anything can happen.
Mosheh Gains contributed to this report from Virginia and Ellen McKeefe from Florida.