MILWAUKEE President Barack Obama and Mitt Romney entered their final weekend of campaigning Saturday facing a stubborn landscape of competitive states that are producing equal shares of hope and fear amid conflicting signals about the outcome.
The president, fighting to avoid being turned out of office four years after a rousing and historic victory, sought to shore up his standing in Midwestern states that had backed him enthusiastically last time. He assumed a defensive posture in Iowa and Wisconsin, two states where his advisers had openly scoffed at his rival's chances only months ago.
Romney, in the closing days of his second quest for the White House, worked to harness the enthusiasm running through the Republican Party to overcome the challenges he confronts in building an Electoral College majority. He fought to secure critical states like Florida and Virginia without allowing others to slip away.
But after hundreds of millions of dollars in television commercials, months of campaigning and three widely viewed debates, the race was locked in the same dynamic that has defined it from the start: Obama, burdened by four years of economic struggle and partisan animosity but still an inspiration to his party, holding the slightest of edges in Ohio and other swing states, and Romney, bearer of the hopes of conservatives and voters convinced the nation is on the wrong path, fighting to overtake him.
The last defining question was whether Romney's support had hit a ceiling blunted by Obama's opportunity to show leadership in the deadly aftermath of Hurricane Sandy or whether he was on the verge of unseating a president in a dramatic finale.
Supporters, donors and advisers to Romney, in battleground states and at the campaign headquarters in Boston, said in conversations over the past two days that they had hoped to be closing the campaign in a stronger position, with clear leads in at least some of the battleground states. Now, several of them said, their optimism comes from the uncertainty in the closing hours of a contest, rather than any affirmative command of the race.
Obama raced through four states Saturday as he tried to build enthusiasm among Democrats, appearing after a performance by singer Katy Perry to urgently tell a crowd of thousands, "We have come too far to turn back now; we have come too far to let our hearts grow weary."
And Romney sought to tap into disappointment and discontent among voters as he rallied supporters, telling a rally in Portsmouth, N.H., "He's offering excuses. I'm offering a plan. I can't wait to get started."
The outlook expressed by both campaigns belied the tight nature of the contest in at least seven states. In their respective headquarters, advisers made convincing cases for why their candidate had the clearer path to 270 electoral votes, but when pressed they admitted to sleepless nights about a result that was expected to come down to a sliver of the electorate.
The pursuit of Ohio's 18 electoral votes drew the most attention, with the candidates scheduling multiple stops there before Tuesday, but the rest of the landscape was also highly volatile. Obama had the edge in Nevada and Romney in North Carolina, strategists agreed, while Colorado, Florida, Iowa, New Hampshire, Virginia and Wisconsin were far closer.
In Wisconsin, Romney rallied voters Friday as his running mate, Rep. Paul Ryan, a native son, fought to rewrite the historical trends of a state that has not voted for a Republican presidential candidate since Ronald Reagan in 1984. Republicans lost the state by only a hairsbreadth in 2000 after George W. Bush spent months tirelessly campaigning.
Obama, who carried Wisconsin by 14 percentage points in 2008, arrived in Milwaukee on Saturday afternoon. His campaign advisers thought the contest here was narrow enough to send him back to the state Monday for a rally with an even bigger music star, Bruce Springsteen.
"It's always tantalizingly close for Republicans, and I assume that's where we are at with this one," said James E. Doyle, a former Democratic governor of Wisconsin who was among Obama's early supporters.
The defeat of an attempt to recall Gov. Scott Walker of Wisconsin, a Republican, this year left behind a well-trained contingent of voters that Romney and his team will try to return to the polls. State laws that allow same-day registration in Wisconsin and Iowa were seen by advisers to the Obama campaign as an advantage in their efforts to turn out younger voters.
Neil Newhouse, the pollster for the Romney campaign, compared the moment in the race to a football game: "It's a tie game, and there's a loose ball."
Joel Benenson, the pollster for the Obama campaign, argued instead that Obama held the edge and that Romney was running out of time to overcome him.
Strategists on both sides agreed that Hurricane Sandy had at the very least interrupted Romney's late-stage prosecution of Obama in a way that may have stunted the sense of momentum that had been surrounding his campaign.
The duel between Obama and Romney also held implications for the fight for the Senate, where Democrats are increasingly hopeful of retaining control, as well as for races in the House, where Republicans are confident of keeping their majority.
A burst of campaigning took place Saturday, with Vice President Joe Biden, former President Bill Clinton and other Democrats leading the charge for their party and Ryan and Republican governors fanning across the country.
The close nature of the presidential race was underscored by the travel schedules, which left the candidates crossing paths, including stops Saturday afternoon only a few miles apart in Dubuque, Iowa, across the Mississippi River from Wisconsin. Four years ago, Obama carried Iowa and Wisconsin by wide margins, but he has struggled to lock down his support this year, creating an opening for Republicans.
"He's trying to do everything he can to rekindle what he had four years ago, but it's not there," said Gov. Terry E. Branstad of Iowa, a Republican. "Initially, there were a lot of people who were against Obama and weren't that wild about Romney, but over the last few months that has changed, and now there is really genuine enthusiasm for Romney."
The candidates are intimately familiar with the metrics and minutiae of the state-by-state races. In Iowa, for example, Democrats were pointing to 17,000 voter registrations in the past month, which narrowed the Republican advantage to about 1,400 voters, down from about 11,000 a month ago.
The campaign played out Saturday entirely on the terrain Obama won four years ago, when he expanded the battleground to Virginia and North Carolina for the first time in a generation. Republicans portrayed Romney's late push into Pennsylvania, where he was set to have a campaign rally today, as a sign of strength.
"You have to look at what they're doing now," said Gov. Tom Corbett of Pennsylvania, a Republican. "They're engaging here. They're spending money here. The race is close, and that's when you try to push it over the line."
Yet Democrats portrayed the move as an act of desperation, arguing that the state has not voted for a Republican presidential candidate since George H.W. Bush in 1988. The Democratic Party also has a voter-registration advantage of more than 1 million people in Pennsylvania.
In interviews, aides to Obama said he remained competitive in Florida, a state that both sides had viewed as more favorable to Romney, who would face a hard road to victory without its 29 electoral votes. Obama officials said they were benefiting from outsize support from non-Cuban Latino groups and strong turnout in early voting in Miami-Dade and Broward counties.
Romney's campaign officials said they were confident that he would win Florida. But they were not taking chances and scheduled a Monday visit by Romney.