Obama will visit New Jersey, the state hardest hit by the storm which hammered much of the northeastern United States, accompanied by Gov. Chris Christie. The governor has been one of Romney's most prominent supporters, but he has been effusive in his praise of Obama's response to the storm.
Though Obama has suspended campaigning for three days in a tight race and New Jersey is safe Democratic territory, the tour with Christie offers him clear advantages. Obama can appear to be in command, directing U.S. aid and showing concern for the storm's victims. The appearance with Christie also makes him look bipartisan at a time of deep division in U.S. politics.
Romney, meanwhile, must walk a careful line. Aggressive attacks on Obama could appear unseemly during a national crisis. Yet he is running out of time to make his case to voters ahead of Tuesday's vote.
Polls show the candidates virtually tied. But the winner will be determined in state-by-state votes, and a handful of states that are not clearly Democratic or Republican will determine the outcome. Obama appears to have a slight lead in the state tallies.
Obama's campaign announced Wednesday he planned to resume campaign travel Thursday after a three-day pause with stops in Nevada, Colorado and Wisconsin.
The president's actions have forced Romney to make tough choices. The former Massachusetts governor must show respect for the superstorm's casualties, but he can ill afford to waste a minute of campaign time, with the election six days away.
After tamping down his partisan tone Tuesday at an Ohio event that emphasized disaster relief, Romney returned to a robust campaign message in events in Florida, the largest competitive state. Sandy largely spared Florida.
"This is quite a time for the country. We're going through trauma in a major part of the country, the kind of trauma you've experienced here in Florida more than once," Romney said, and he encouraged donations to the Red Cross. He then launched into a critique of Obama's leadership in tough economic times and said he would do better.
"I don't just talk about change. I actually have a plan to execute change and make it happen," Romney said.
Romney's shifting stances on a number of key issues have haunted his campaign. After the superstorm battered the East Coast, Romney was sounding far more supportive of federal government assistance to states ravaged by the natural disaster. Only last year, as Romney leaned to the right while battling for the Republican nomination, he appeared to suggest in a debate that the Federal Emergency Management Agency should be shuttered and its responsibilities left to the states.
He sounded a different message on Wednesday.
"I believe that FEMA plays a key role in working with states and localities to prepare for and respond to natural disasters," Romney said in a statement. "As president, I will ensure FEMA has the funding it needs to fulfil its mission, while directing maximum resources to the first responders who work tirelessly to help those in need, because states and localities are in the best position to get aid to the individuals and communities affected by natural disasters."
Romney's position put forward Wednesday essentially endorsed the current disaster aid system.
Obama left Wednesday's sharp-elbowed politicking to Vice-President Joe Biden, who accused Romney of perpetrating "an outrageous lie" in an ad airing in key battleground state Ohio that suggests Obama's policies are shipping Jeep manufacturing to China. Biden told Florida voters that the ads are "scurrilous" and "one of the most flagrantly dishonest ads I can ever remember in my career," which stretches more than 40 years.
Romney's campaign has stood by the ad, which also was criticized by auto executives. "Their comments don't refute anything in our ad," said Romney spokeswoman Andrea Saul.
To the independent and undecided voters sick of the political swampland of Washington, Obama appeared bipartisan by co-operating on storm work with prominent Romney supporter Christie.
"The president has been all over this, and he deserves great credit," Christie said in a TV interview Tuesday. By contrast, when Christie was asked whether Romney was coming to help, he said, "I have no idea, nor am I the least bit concerned or interested."
Some Republicans quickly criticized Christie for praising Obama.
Associated Press writers David Espo, Julie Pace, Connie Cass, Gary Fineout, Steve Peoples and Kasie Hunt contributed to this report.