Barack Obama declared he wanted to "win everywhere" as the two-year race for the White House entered its final weekend.
The Democratic presidential nominee leads his Republican rival John McCain by more than six points in the latest average of national polls by RealClearPolitics.com.
Mr Obama is now fighting his campaign on the Republicans' home turf as Mr McCain struggles to defend states like Virginia that have usually been safely locked up by the Republican candidate this late in a presidential campaign.
He aired adverts in Georgia and North Dakota and even in Mr McCain's home state of Arizona as Americans prepared to cast the last votes of the election on Tuesday.
Asked about the adverts showing in traditionally Republican states, Mr Obama said: "We want to win everywhere."
And as he personally delivered the Democratic Party's weekly radio address, the 47-year-old Illinois senator said: "If you give me your vote on Tuesday, we won't just win this election - together, we will change this country and change the world."
On the campaign trail in Virginia, Mr McCain urged supporters to help him stop the Old Dominion State from tipping to Mr Obama.
"We need to win Virginia on the fourth of November," he said.
"With your help we're going to win."
The 72-year-old Republican coughed and sounded hoarse at the chilly rally in the conservative region which has a large military presence.
The state has not voted for a Democrat since Lyndon B Johnson in 1964 but polls show Mr Obama with the upper hand.
Mr McCain claimed his rival would seek tax increases as president and said: "He's running for redistributor in chief, I'm running for commander in chief."
On Friday night, California governor and former Hollywood actor Arnold Schwarzenegger declared Mr McCain was the "real action hero" at a rally in Columbus, Ohio.
The Terminator actor offered to help Mr Obama beef up his "skinny legs" and "scrawny little arms" and said: "John McCain has served his country longer in a PoW camp than his opponent has in the US Senate.
