Two days from judgment by the voters, U.S. President Barack Obama raced through four far-flung battleground states on Sunday while opponent Mitt Romney ventured into traditionally Democratic Pennsylvania — where registered Democrats outnumber Republicans by nearly a million — seeking a breakthrough in a close race.

"I won't just represent one party. I will represent one nation," Romney told an audience chanting "U.S.A" in Morrisville, Pa., Sunday evening.

The former Massachusetts governor also touched briefly on education, families, the military and, once more, on revenge voting.

"We're a generous people. We give to others in need," Romney said. "On November 6th we can come together for a better future, and on November 7th we're going to get to work."

On Sunday morning, Obama headed to New Hampshire, where former president  Bill Clinton joined him at a rally in Concord. Obama will later travel to Florida, Ohio and Colorado.

Clinton joked at the New Hampshire rally that there's a "rampant virus" going around called "Romnesia," explaining that when Romney predicted the economy would produce 12 million jobs over four years if he won, he forgot to mention a Moody's Analytics forecast released in August before that promise, saying the U.S. will gain that number of jobs "if we just don't mess with what the president has already done." 

After a campaign that began more than a year ago, late public opinion polls were unpredictably tight for the nationwide popular vote. But they suggested an advantage for the president in the state-by-state competition for electoral votes that will settle the contest.  

Conceding nothing, Romney set his first foray of the fall into Pennsylvania. The state last voted for a Republican presidential candidate in 1988, but the challenger and his allies began advertising heavily in the campaign's final days. 

"He's offering excuses. I've got a plan" to fix the economy. "I can't wait for us to get started," Romney said in a new television commercial, possibly the last of the campaign, as he appeared in Iowa, Ohio and Virginia as well as Pennsylvania. 

In Des Moines, he said he would meet regularly with "good men and women on both sides of the aisle" in Congress. Later, in Cleveland, he said of Obama, "Instead of bridging the divide, he's made it wider." 

Obama had New Hampshire, Florida, Ohio and Colorado in his sights for the day, and judging from the polls, a slight wind at his back. So much so that one conservative group cited a string of surveys that favor the president as it emailed an urgent plea for late-campaign donations so it could end his time in the White House.

"I think the effort probably is more to inspire voters to get out and vote rather than to try to persuade them as to the campaign argument this late in the game," CBC's Washington correspondent Keith Boag said.

In New Hampshire, the president said he wants to work across party lines, but said he won't give up priorities such as college financial aid or the health care law he pushed through Congress.  

"That's not a price I'm willing to pay," he said, a reference to Romney's frequent pledge to dismantle the health law that Republicans derided as "Obamacare." 

As they did about almost everything else in the campaign, aides to Obama and Romney disagreed about the political significance of the early voting. 

"Early voting is going very well for us," said David Plouffe, a top White House aide, adding a prediction on ABC's This Week that the president will win a second term on Tuesday. 

Romney strategist predicts victory

But Rich Beeson, Romney's political director, said "they are underperforming and we are overperforming" in terms of turning out early and absentee votes turned compared with 2008. Romney and Wisconsin Rep. Paul Ryan "will be elected the next president and vice president of the United States," he predicted on Fox News Sunday.

Obama's term has been littered with the legislative wreckage left behind by constant struggles with congressional Republicans. Yet his trip to New Jersey last Wednesday was a model of nonpartisanship as he accompanied Republican Gov. Chris Christie on a tour of destruction caused by Superstorm Sandy. The governor repeatedly praised the administration's response to the storm. 

One prominent Republican said the storm had worked to Romney's disadvantage in a different way. 

"The hurricane is what broke Romney's momentum. I don't think there's any question about it," former Mississippi Gov. Haley Barbour said on CNN's State of the Union.  

Romney's campaign wanted no part of that.  "I don't look at what happened with the storm and how it affected so many people through a political lens," said a spokesman, Kevin Madden.