Boca Raton, Florida (CNN) -- A dramatic new consensus has taken hold inside the campaigns of President Obama and Mitt Romney, one that was unthinkable just a few weeks ago: Americans will wake up on Election Day not knowing who their next president will be.
Polls have tightened, with trend lines in several key states favoring Romney, and Monday's foreign policy debate in Florida doing little to radically alter the shape of the race.
Romney spent much of the year working to shore up his conservative flank. But now, buoyed by his vigorous first debate performance, he plans to spend the remainder of the campaign visiting swing precincts where both campaigns are competing for a diminishing slice of undecided or persuadable suburban women.
Obama campaign officials now privately acknowledge that North Carolina, a state they can afford to lose, is moving perilously out of reach. Polling shows Florida also moving slightly toward Romney, but few in either camp believe the Republican nominee has more than a 1- or 2-percentage-point edge here.
Both campaigns consider Virginia and Colorado tight.
New Hampshire is now a jump ball, and the Romney campaign is making a last-minute investment on expensive Boston area television ads in an attempt to turn the state red.
The president's re-election chances increasingly hinge on a "Big Ten" firewall of Iowa, Wisconsin and, most importantly, Ohio -- a state where Romney has been stymied by his opposition to the federal auto bailout and a concentrated effort by Obama forces to portray the former private equity whiz as out of touch with the middle class.
The Obama campaign is highlighting polls showing robust leads in early voting and absentee balloting in Iowa and Ohio, but Republicans have worked to close the wide early voting gap that helped drive Obama's victory in 2008.
Still, both campaigns are seeing the race narrow in those Midwestern states, which just weeks ago were thought to be firmly in Obama's grasp.
Even some Democrats admit that, for the moment, the momentum is on Romney's side.
"What is holding the president back is voters still don't know what he is going to do early next year to get this economy going," Democratic pollster Celinda Lake said. "There is still time for him to do that, because the economy is the No. 1 thing people are paying attention to."
The president is working to correct that, launching a fresh effort Tuesday to define his second-term vision with a new minute-long television ad airing in all the key battlegrounds.
Romney aides, who have been gripped by an unfamiliar feeling of optimism and excitement since the first debate, say it's too late for the president to reinvent himself.
"The president being at 46, 47%, that would scare the crap out of me if I'm the incumbent," Romney adviser Russ Schriefer said of the president's approval rating, which has recently hovered just below 50%.
Romney's latest campaign theme -- that he is a firm and resolute leader with a clear plan to fix a rudderless economy -- infuriates Obama advisers, who scoff at the idea that someone who has veered wildly from message to message throughout his campaign is suddenly a more trustworthy option than the president.
But Republicans outside the campaign say Romney has finally put his finger on a credible message at precisely the right moment.
"If the election were held today, I think Obama might squeak out a win, but he is now playing defense and running a very small campaign," said Steve Duprey, a Republican power player in New Hampshire who advised John McCain's presidential campaign. "Contrast that with Romney, who sounds optimistic and sunny. People like to see someone who has momentum and see someone who has positive, sunny rhetoric."
Talk has percolated in Romney-world that a late advertising push might be possible in Democratic-leaning Michigan and Pennsylvania, where Obama has long been considered safe.
One high-ranking Romney official, granted anonymity to speak frankly about campaign tactics, admitted that Michigan is probably off the table because Democrats "have done such a job of sticking a knife in us on the auto bailout."
But Pennsylvania, with 20 electoral votes and no early voting, remains an intriguing smash-and-grab possibility for Romney media buyers if the polls there remain within the margin of error the week before Election Day.
Democrats call that talk nothing more than a head fake -- Obama campaign manager Jim Messina answered with a flat "no" when asked if Pennsylvania is a battleground state -- but the Romney campaign and the Republican National Committee have kept more than 60 staffers in the state since last spring.
The Obama team insists it always knew the contest was going to tighten in its final stage, though it's commonly acknowledged among Democrats that the president's dismal first debate showing was a colossal self-inflicted wound.
Despite the avalanche of ads currently swamping television airwaves, the race will now be decided by the "ground game," a fundamental but often little-understood aspect of campaigns focused on the mechanics of voter identification, persuasion and turnout.
Despite Republican advances since 2008 in field work and early voting, which started in Iowa in late September and is under way in five other swing states, few in either party question the supremacy of the Obama ground operation.
Obama supporters say their early investments in staff and field offices in key battlegrounds -- the campaign has been deeply embedded in Ohio, where it has over 130 offices, since the epic Democratic primary fight of 2008 -- will carry the day in November.
"We think we are going to do a terrific job on turnout," said Obama adviser David Plouffe. "You can find any poll you want out there to fit your judgment on the race, but the president has had a very strong position in these battleground states. We still think we have a more credible pathway to 50% in Florida than Gov. Romney does. We certainly feel that way in Virginia, in Ohio, in Nevada, in Iowa, in New Hampshire. Even in North Carolina."
The razor's-edge race presents an opportunity for the Obama campaign to validate its long-held theory that a superior field operation combined with subtle demographic shifts in the electorate will provide a cushion for the president.
Florida, with more than 11 million registered voters, is a proving ground for that hypothesis.
In the last four years, the number of registered Hispanic voters in Florida has jumped by almost 200,000, and more of them have registered as Democrats than Republicans. The number of African-American voters has also ticked up by a few points. At the same time, the share of white voters has dipped slightly. Those are all favorable shifts for the Obama campaign.
Obama advisers in Florida see the Orlando area in particular, with its burgeoning Puerto Rican population that leans Democratic, as fertile hunting ground once early voting begins on Saturday.
If the campaign can increase the share of Hispanic vote on Election Day to 15% of the vote, slightly up from 13% in 2008, it believes that winning about two-thirds of those voters might be enough to offset modest losses among white voters or independents.
It's a tightrope walk, but one the Obama campaign has been preparing for since 2009, particularly in states with growing Hispanic populations like Florida, Nevada and Colorado.
Republicans, meanwhile, are hoping that an autumn burst of grass-roots enthusiasm will help them overcome their comparatively late start in the field.
Though the Republican National Committee began laying some early groundwork in key states, the party was not able to fully build out a national get-out-the-vote operation until Romney sewed up the nomination last spring.
Romney's ground effort is built on a fleet of battleground state "Victory Offices," funded and staffed, in part, by the RNC.
While the presidency is the top prize this fall, the GOP Victory effort is not Romney's domain alone -- it's also providing the backbone for key Senate, House and gubernatorial campaigns.
The Obama operation, meanwhile, is devoted solely to re-electing the president, and in most of the pivotal states it has more than twice as many field offices as the Republicans.
Both campaigns are leveraging new technological advancements and sophisticated algorithms to identify and turn out their supporters in the final weeks of the race. They are narrowly targeting their online ads, using cookies, tapping into social networks online to mine personal information, and using iPads for data entry during neighborhood walks.
But the Obama and Romney teams are also betting on strikingly different field models.
Early October visits to Republican Victory offices in central Virginia illustrated both opportunities and challenges for Romney.
Republican enthusiasm was not in question. On a Saturday morning in Henrico and Chesterfield counties, Romney volunteers were streaming in to field offices, signing up for three-hour shifts to make phone calls or knock on doors to identify potential Romney supporters.
The Republican ground effort in Virginia has knocked on almost 1.2 million doors in the commonwealth to date, 12 times as many as it hit in 2008. Academic studies and field experiments have shown that in-person visits are the most effective form of voter contact, more so than direct mail or phone calls.
Volunteers were calling potential supporters, using predictive dialer phones that sent data directly back to the RNC's voter database, which is constantly being refined and examined by microtargeting gurus as the party learns more about the different universes of voters in each key state.
After reaching a voter on the phone, a GOP volunteer would read from a script to determine if that person was supporting Romney or Obama, or if he or she was undecided. Volunteers punched the answers into the phone's keypad during the conversation, adding the latest information to the party's voter list, before hanging up. The phone system would then automatically dial a new voter.
The Victory Office phone calls are only reaching landlines and not cell phones, two GOP sources told CNN.
Republicans have a similar structure in place across the political battlefield, and they have touted a record-breaking number of door-knocks and phone calls made this cycle.
But Democrats say the numbers are inflated, in part because automated messages left on answering machines are being counted as voter contacts.
Along with its door-to-door efforts, the Obama campaign in Ohio is making calls in a more traditional fashion, working off a call sheet and writing down information about voters as it comes in. Voter data is manually entered into the campaign's database each evening.
It's a more labor-intensive method, but campaign officials say it allows them to have a more nuanced understanding of the voters they are trying to persuade and mobilize.
While the Obama campaign has field offices in nearly every corner of every battleground state, organizers say they have even deeper roots than the Romney campaign because of their neighborhood team model, in which local volunteers are empowered with leadership roles in their communities.
Also working in Obama's favor on the ground, albeit counterintuitively: the 2010 Citizens United vs. Federal Election Commission ruling that loosened campaign finance restrictions.
The Supreme Court decision has drawn scorn from liberals and pundits who say conservative groups now have an outsize voice in campaigns, but the ruling also opened the door for organized labor to target all voters, not just traditional union members.
The AFL-CIO has been registering and persuading voters in labor-friendly states like Ohio, Wisconsin and Nevada throughout the year.
Labor officials are now refocusing their efforts on turnout.
Mike Podhorzer, the AFL-CIO's political director, said that recent high-profile battles over labor in the Midwest -- namely the 2011 repeal of a restrictive collective bargaining bill in Ohio and the unsuccessful recall attempt of Gov. Scott Walker earlier this year in Wisconsin -- gave union organizers a chance to "road test" their field strategies before the presidential election.
"We were able to mobilize," Podhorzer said. "It was an opportunity for us for test and implement a number of programs which were very valuable."