BRIGANTINE, N.J. (AP) -- President Barack Obama soberly toured the destruction wrought by superstorm Sandy on Wednesday in the company of New Jersey's Republican governor and assured victims "we will not quit" until cleanup and recovery are complete. Six days before their hard-fought election, rival Mitt Romney muted criticism of Obama as he barnstormed battleground Florida.

Forsaking partisan politics for the third day in a row, the president helicoptered with Gov. Chris Christie over washed-out roads, flooded homes, boardwalks bobbing in the ocean and, in Seaside Heights, a fire still burning after ruining about eight structures.

"I cannot thank the president enough for his personal concern and compassion for our state and the people of our state," Christie, praising what he called "a great working relationship" that started even before the storm hit.

"The president has been outstanding in this," Christie said.

"Gov. Christie throughout this process has been responsive. He's been aggressive in making sure the state got out in front of this incredible storm," Obama added, thanking the Republican for his "extraordinary leadership and partnership."

Said Obama of the governor, "He has put his heart and soul into making sure the people of New Jersey bounce back stronger than before."

The president introduced one local woman to "my guy Craig Fugate." In a plainspoken demonstration of the power of the presidency, Obama instructed the man at the head of the Federal Emergency Management Agency, a 7,500-employee federal agency, to "make sure she gets the help she needs" immediately.

Despite the tour and Romney's own expressions of sympathy for storm victims -- a break on the surface from heated campaigning -- a controversy as heated as any in the long, intense struggle for the White House flared over the Republican challenger's new television and radio ads in Ohio.

"Desperation," Vice President Joe Biden said of the broadcast claims that suggested automakers General Motors and Chrysler are adding jobs in China at the expense of workers in the bellwether state. "One of the most flagrantly dishonest ads I can ever remember."

Republicans were unrepentant as Romney struggled for a breakthrough in the Midwest.

"American taxpayers are on track to lose $25 billion as a result of President Obama's handling of the auto bailout, and GM and Chrysler are expanding their production overseas," said an emailed statement issued in the name of Republican running mate Paul Ryan.

The two storms -- one inflicted by nature, the other whipped up by rival campaigns -- were at opposite ends of a race nearing its end in a flurry of early balloting by millions of voters, unrelenting advertising and so many divergent polls that the result was confusion, not clarity.

In the race's final days, Romney's campaign aired ads in Minnesota and Pennsylvania, two states long considered safe for the president. Republican's allies are airing commercials in Michigan and New Mexico.

Obama's aides insisted the states were safe for him, but it dispatched former President Bill Clinton to Minnesota, and purchased airtime in the other three states to respond to the Republicans. 

Obama's aides said the president would return to political travel on Thursday with stops in Wisconsin, Nevada and Colorado. But for one more day, he was hands-on commander of the federal response to Sandy, and consoler-in-chief for its victims. 

National surveys make the race a tight one for the popular vote, with Romney ahead by a statistically insignificant point or two in some, and Obama in others.

Both sides claim an advantage from battleground state soundings that also are tight. Obama's aides contend he is ahead or tied in all of them, while Romney's team counters that his campaign is expanding in its final days into what had long been deemed safe territory for the president in Michigan, Pennsylvania and Minnesota.

The storm added yet another element of uncertainty, as Obama spent a third straight day embracing his role as incumbent and Romney tried to tread lightly during a major East Coast disaster.