On the heels of the campaign's final debate, the Democrat is launching TV ads in West Virginia, which George W. Bush won four years ago and hadn't been on the list of target states until recently, according to two Democrats with knowledge of the strategy.
Obama lost West Virginia in the Democratic primary to Hillary Rodham Clinton as he struggled to win over working-class whites. But Democrats say the economic turmoil in the hard-hit state and TV ads Obama has been running in its neighbors have made West Virginia competitive. These Democrats spoke on the condition of anonymity to avoid angering the campaign.
They say Obama's campaign also is considering pouring money into reliably Republican Kentucky and may yet return to the airwaves in North Dakota and Georgia. Those are two states Obama had tried to put in play over the summer, but he pulled out when they appeared out of reach.
The Illinois senator sounded increasingly optimistic at a breakfast fundraiser at the New York City Metropolitan Club.
"We now have 19 days," Obama said. "We are now 19 days not from the end but from the beginning. The amount of work that is going to be involved for the next president is going to be extraordinary."
But, he said, for anyone getting cocky or giddy, "two words for you: New Hampshire. I've been in these positions before where we were favored and the press starts getting carried away, and we end up getting spanked." Obama won the Iowa caucuses, only to lose to Clinton in New Hampshire in the primary.
McCain, for his part, was returning to the argument that Obama's credentials are too thin for the White House, his campaign and the Republican National Committee releasing ads focusing on experience and judgment.
McCain planned to visit swing state Pennsylvania, but he also was being forced to go to Republican territory as polls show Obama with the edge in such places as Virginia, Colorado and Florida. Obama was heading in the next few days to Virginia and Missouri, states often out of reach for Democrats but up for grabs in a year with Republicans under fire.
Wednesday night, McCain tried to blunt a familiar line of attack when he asserted, "Sen. Obama, I am not President Bush." But Obama quickly turned that argument against his rival in a new TV spot. "True," the ad's announcer responds, "but you did vote with Bush 90 percent of the time."
According to a CBS News/Knowledge Networks poll, uncommitted voters named by a large margin.
One unique debate watcher was "Joe the Plumber" - Joe Wurzelbacher of Holland, Ohio, whose exchange with Obama about taxes and small businesses a few days earlier elicited dozens of references from the candidates during the debate.
"It floored me. It's not something I expected, ever," Wurzelbacher told "Good Morning America" on ABC. Though he wouldn't say for whom he was voting, Wurzelbacher said Obama had a "very socialist view" of taxes "and that's incredibly wrong."
The 90-minute debate at Hofstra University marked the beginning of a sprint to Election Day. Obama leads in the national polls and in surveys in many battleground states, an advantage built in the weeks since the nation stumbled into the greatest economic crisis since the Great Depression.
Looking to shake up the race, McCain questioned Obama's character and his policies. He linked Obama to a 1960s radical, accused him of planning tax increases that would cripple the economy and said he was dishonest about a promise to accept public campaign financing.
"You didn't tell the American people the truth," the Arizona senator said.
Obama ignored that charge and remained calm throughout the debate. He often turned the accusations against McCain, calling them examples of the petty politics harming the country.
"The important point here is, though, the American people have become so cynical about our politics, because all they see is a tit-for-tat and back-and-forth," the Illinois senator said. "And what they want is the ability to just focus on some really big challenges that we face right now."
McCain went on offense from the opening moments, accusing Obama of waging class warfare by seeking tax increases that would "spread the wealth around."
He also demanded to know the full extent of Obama's relationship with college professor William Ayers, once a Vietnam War protester and part of a group that bombed government buildings, and the Democrat's ties with ACORN, a liberal group accused of violating federal law as it seeks to register voters. McCain said the group could be on the verge of "destroying the fabric of democracy."
Obama condemned Ayers' violent activities and denied any significant ties to ACORN, mocking McCain for bringing them up.
"I think the fact that this has become such an important part of your campaign, Sen. McCain, says more about your campaign than it says about me," he said.