– By JOHN MCCORMICK

and LISA LERER

Additional Photos

ASSOCIATED PRESS

ASSOCIATED PRESS

Bloomberg News

The presidential race resumed Thursday with frenetic candidate schedules as polls show the most costly contest in U.S. history could yield a split decision.

Some national polls give Republican Mitt Romney a slight edge in the popular vote — although well within the polls’ margin of error — while surveys show President Obama ahead in a number of the most competitive states, which would hand him an Electoral College victory and a second term in the White House.

Don Kettl, dean of the University of Maryland School of Public Policy, said he anticipates a “very, very close” popular vote outcome and doesn’t discount the possibility of a split decision between the electoral and popular votes.

Obama returned to a full campaign schedule Thursday with stops in Wisconsin, Nevada and Colorado after spending the first part of the week focusing on the federal response to Atlantic superstorm Sandy. On Wednesday, he visited hard-hit New Jersey to survey damage with Gov. Chris Christie, a Romney campaign surrogate who was the keynote speaker at the Republican nominating convention.

Obama and Christie set aside their political differences to praise each other for their responses to the storm. Christie said the president “has sprung into action immediately,” while Obama said the governor displayed “extraordinary leadership.”

Romney, who had scaled back campaigning this week because of the storm, returned to a full-fledged schedule Wednesday as he crisscrossed Florida, the largest electoral prize among the nine states that both sides say are most likely to determine the outcome. On Thursday he was in Virginia, another of the main battlegrounds.

The Washington Post/ABC News national tracking poll released Wednesday showed Romney and Obama tied at 49 percent among likely voters, based on interviews conducted Oct. 27-30. An aggregation of national polls compiled by the website RealClearPolitics also showed a tied race as of Wednesday night, with each candidate at 47.4 percent, while several other surveys individually gave an edge to Romney.

The picture looks different in state surveys, with a small but clear advantage for the president in these races.

The RealClearPolitics aggregation of polls in the nine most closely contested states gives Obama the advantage in Ohio, Wisconsin, Nevada, Iowa and New Hampshire. Wins by Obama in those states, as well as in the others across the nation most analysts have predicted he will carry, would give him 281 electoral votes, 11 more than needed for a second term. The website’s aggregation of polls for other swing states shows Colorado a virtual tie — with Obama up by 0.5 percentage points — and Romney ahead in Florida, Virginia and North Carolina.

A separate aggregation of polls on the Huffington Post, which in 2010 acquired the Pollster.Com website, shows Obama leading in seven of the nine states, with Romney having the advantage in Florida and North Carolina.

A poll released Wednesday in Ohio, the state where the campaigns are competing the most aggressively, showed Obama slightly ahead. The president was backed by 48 percent of likely voters in the Ohio Poll, which is sponsored by the University of Cincinnati, while Romney had the support of 46 percent. The survey was taken Oct. 25-30 and has a margin of error of plus or minus 2.9 percentage points.

A split verdict between the national vote and the Electoral College count has happened four times in U.S. history. The most recent instance was in 2000, when Vice President Al Gore won the popular ballot count by about 500,000 votes while Texas Gov. George W. Bush eked out the win with 271 electoral votes after a U.S. Supreme Court ruling set the stage for him to carry Florida by 537 votes.

“The odds are strongly against it, although it doesn’t mean it won’t happen,” David Redlawsk, a political science professor at Rutgers University in New Brunswick, N.J., said of the prospects for a similar split this year. “The state-level polling seems to be putting Obama up and it would be somewhat surprising if the national numbers didn’t follow that.”

If there is a split decision, he said he doubts it will be because of depressed turnout in Democratic-leaning states such as New York and New Jersey because of the storm.

“Most people who intend to vote will find a way to vote,” he said. “I don’t subscribe to the idea that there will be a significant depression of turnout.”

Romney has struggled to overcome an electoral map that works against him, in part because many of the country’s most populous states — including California and New York — lean Democratic. That gave Obama an opening edge in the electoral math.

In recent days, Romney and his allies have plunged into traditionally Democratic ground, escalating their campaign efforts in a trio of states — Minnesota, Pennsylvania and Michigan — that they had largely ignored.

With polls showing Obama maintaining a lead in Ohio, Romney’s team may be searching for paths other than winning that state to get to the 270 electoral votes needed to claim the White House.

Romney aides say they remain confident about their chances in Ohio and see an opportunity to expand the number of states in play.

“We feel like we’re confident we’re on offense and that we’re in a great position to win on Election Day,” spokesman Kevin Madden told reporters on Romney’s campaign plane Wednesday.

Romney pollster Neil Newhouse said the public’s discontent about the direction of the country and disapproval of Obama’s performance will affect turnout, giving the Republican just as much support as the president will have among his core supporters while boosting Romney’s backing among the independents who will decide the contest.

“You take a step back from this, you’ll see exactly what this is: a very tight race that is very far from being decided right now,” Newhouse said.

Obama’s political advisers sought to project confidence even as most national polls showed the race deadlocked.

“At this time next week, President Obama will have been re-elected for a second term,” Obama campaign manager Jim Messina said on a conference call Wednesday.

“We have the map and they have the myths,” he said, referring to the fight for key states and assertions by the Romney camp that the race is turning the Republican’s way.