CHICAGO - This is what "grinding it out" looks like at President Obama's election headquarters: scores of young staff members crunching gigabytes of data about which way undecided voters are leaning, where they can be reached and when; strategists standing at whiteboards writing and erasing early voting numbers and turnout scenarios; a lonely pingpong table.

The wave of passion and excitement that coursed through Obama's headquarters in 2008 has been replaced with a methodical and workmanlike approach to manufacturing the winning coalition that came together more organically and enthusiastically for him in the last go-round, a more arduous task with no guarantee of success.

As Washington and the cable news commentariat breathlessly discuss whether Mitt Romney's post-debate movement in the polls has peaked, Obama's campaign technicians -- and that's what many of them are -- are putting their faith as much in the multimillion-dollar machine they built for just such a close race as in the president himself.

"We are exactly where I thought we would be, in a very close election with 12 days left with two things to do and two things only: persuade the undecided and turn our voters out," said Jim Messina, 43, the president's campaign manager.

Pointing to the rows and rows of personnel outside his office Thursday, he added, "Everything in that room has been focused on that."

Four years ago, Obama's team was preparing another one of its showstoppers: a half-hour prime-time program extolling Obama's background and character across four networks, culminating in a live feed from a rally in Florida.

Microtargeting supporters

There will be no such razzmatazz this time. Any extra money in this tight, final phase of the election is being wired to Nevada and Florida for more Spanish-language ads, to Iowa and Ohio for more on-the-ground staff members, and to Google and Facebook for more microtargeted messaging to complacent, maybe even demoralized, young supporters.

For Obama's campaign staff in a nondescript office tower, the task now comes down to creating an electorate more favorable to Democrats than most major pollsters have assumed, with percentages of Obama-friendly black, Latino and young voters that rival those of 2008, at least enough to offset the large drop in support among other segments of the population, like independent men.

Twelve days will tell whether they are bluffing. An ABC News/Washington Post tracking poll Thursday had Romney with a 50 percent to 47 percent edge among likely voters nationwide, the first time the challenger had reached 50 percent in the poll. But Obama's aides are at least projecting an air of confidence that their system, the construction of which began long before Republicans cast their first primary season votes, is working as they hoped it would.

After using their huge data- base to increase registration among favorable voting groups in crucial states, they are now pinpointing people who ordered absentee ballots and need a nudge to send them, or sporadic voters who indicated they would vote for the president but may need to a push to show up at their polling place.

"We made a strategic choice very early on that getting our supporters -- and the right type of supporters -- to the polls before Election Day was a big priority for us," said Mitch Stewart, the Obama campaign's battleground state director, who has been helping organize Obama's supporters since the 2008 election and started at the campaign two years and, in his words, "20 pounds ago."

Trying to motivate voters

There is little dispute that for Obama to at least come close enough to matching his 2008 coalition to win he will need to induce people to vote in a way he did not have to four years ago, before the full impact of the Great Recession was followed by intensive partisan wrangling that took the wind out of some supporters.

Obama's aides said that they had prepared for the need to rebuild his coalition and that is why they have kept careful tabs on his former supporters, and worked to identify potentially new ones, all the while perfecting ways to keep track of them, keep in touch with them and, ultimately, persuade them to vote.

It is why, in the final two weeks, the campaign is refocusing its advertising to scare its less motivated supporters to vote. One new ad flashes a reminder of Al Gore's loss to President George W. Bush in the Florida recount of 2000, which, the ad says, made "the difference between what was and what could have been."

But ultimately, if Obama does win, it could come down to the huge room of technicians and data crunchers in a corporate office, sitting on exercise balls or squeezing stress toys as they dispatch information to volunteers knocking on doors hundreds of miles away and watch the countdown of the very last minutes and seconds.