Here, across 50,000 square feet of fawn-coloured carpet with row upon row of desks and office chairs (and one blue ping-pong table), are the people - about 200 so far - whose job it is to bring Barack Obama back for a second term. Some have been at it since April even though the general election is not until November. Midway through our tour, we are briefly interrupted by rippling applause as a new intake of bodies arrives on the floor to take up their duties.
The first surprise may be that his re-election team is here rather than in Washington. Chicago is where Mr Obama sprung from to become a US Senator and where his 2008 campaign, first against Hillary Clinton in the primaries and then John McCain, was based. Nostalgia is nice, but it is also a long way from the Oval Office where the President necessarily sits most of the time and is a city still popularly associated with corruption in politics.
The other is that, so far, no one here has been formally assigned to research the particular topics of Romney, Paul, Gingrich or Perry, names of just four of the runners in the rambunctious Republican nomination race. They say - we don't have to believe it - they have more important things to do than fixate on other side's impending primary derby. That doesn't mean they won't talk about the other side if pressed and in terms that aren't always polite.
The precise moment when incumbents change tack from being commander-in-chief to candidate-in-chief is often hard to discern. For now, his aides insist, that Mr Obama is still aloof from all things campaign and they cannot tell you when he will make his first foray in formal vote-getter mode. Come to this building and this floor, however, and you will know that in all other respects his re-election effort is already in full swing and has been for a while.
"Of course there are similarities," my guide, a senior member of the team and a veteran of the 2008 race, suggests. (The rules say she must remain anonymous also.) "But the scope of it is much further advanced this time, particularly in the time frame we're at".
Herein lies one of the advantages held by Obama. He knows he is his party's nominee already, so why not get everything cranked up as soon as possible? He has the money for it. The campaign reports that 40 per cent of the cash raised so far has come from donors who did not give in 2008.
It takes an hour to see everything buzzing inside the Obama 2012 hive. There is the media relations corner, where we begin, with TVs tuned to Fox, CNN and MSNBC in that order, and the offices of the top brass, including Jim Messina, the campaign manager. Usually lurking also is David Axelrod, the former White House political counsellor and Chicago native, who is deeply engaged with the re-election effort but is not on its daily payroll.
As we track deeper we visit desks that are home to everyone from field directors, who must stay in daily touch with campaign officers in all 50 states, electoral legal eagles who watch out for skulduggery on the ground that might give the other side an unfair advantage (Pennsylvania is tricky right now), to the digital and technological gurus who write the Tweets and design the logos, the video clips and, most importantly, the Obama 2012 web site, a state-of-the-art thing because it grows and shrinks according to whether you are on a laptop, tablet or phone. There is a call centre, manned by volunteers, a financial area where the accountants sit and even a large surrogates casting department that will deploy folk to speak at events on Mr Obama's behalf when he is busy running the country.
True the TVs in are wheeled out whenever a Republican debate is on (and there have been many) so everyone on the floor can watch, but it seems as if any effort to handicap each of the Republican hopefuls would be frowned upon as a waste of everyone's time. Perhaps it's wise since the polls show the Republican candidates taking their turns almost weekly to steal the pole position from Mitt Romney, the former Governor of Massachusetts.
"If we had tried to guess who that other person was going to be we would have found ourselves changing course six times already," my host explains. "Whoever it is, we will have a campaign operation built ready to face them. It's about getting votes and getting our ground game ready. Honest to God, we are self-focused for now."
Messina and Axelrod insist that their priority is identifying the paths to Mr Obama garnering the 270 electoral college votes that he needs win again in November. They see five in all, assuming the President holds onto all the states that Senator John Kerry held in 2004 when he lost to George Bush. They are: a) Take Florida; b) Take Ohio; c) Take North Carolina and Virginia; d) Take Colorado, New Mexico, Nevada and Iowa and e) Take Arizona.
And they are doing this fully aware of the headwinds against him that have little to with whoever ends up challenging him, with emphasis, of course, on the weak economy and joblessness. The history books tell them that the unemployment rate alone should be enough to doom Mr Obama to becoming the first Democratic president since 1980, when Jimmy Carter was at the end of his first term, to be denied re-election.
Among the top tasks of people in this room is re-energising the old base that put Mr Obama in office and dispelling the sense, as articulated by Matt Damon in a recent magazine interview, that his liberal supporters have lost the faith. "I've talked to a lot of people who worked for Obama at the grassroots level," the actor told Elle. "One of them said to me, 'Never again. I will never be fooled again by a politician.'"
He added: "A one-term president with some balls who actually got stuff done would have been, in the long run of this country, much better."
"He should probably, I would think, win," a slightly coy Richard Mell, a veteran Chicago alderman and a long time friend of Axelrod, offers when asked about the president's prospects. "People like him and he has a lot going for him. But the thing that nags me and a lot of people who talk to me is the fact that this economy is hard right now and an awful lot of people are hurting. If you are out of work or if your wife is out of work or if you're under water with your mortgage, then likely you've made up your mind and it's hard to persuade you on any another issue."
Mr Mell says Obama should be more afraid of Mr Romney than others in the Republican field. A zoological parable that Axelrod famously rehearsed to a group of journalists recently with regard to Gingrich, who briefly led the pack last month, actually came first from Mell. "The higher a monkey climbs on a pole the more you could see his butt ... the speaker is very high on the pole right now and we'll see how people like the view" Axelrod said. (Mell notes that he actually said arse, not butt, but never mind.)
If the Obama crew here won't engage as to which Republican they either want or expect to face - though this week operatives from the Democratic National Committee, based in Washington, have swarmed Iowa to undermine Mr Romney ahead of the caucuses - they will tell you that they are liking the messiness of the process on the other side and the extent to which, in their view, all the runners, including Romney, are allowing themselves to be dragged to the right to appeal to the increasingly radical conservative wing. "I think they are mortgaging themselves" for the general election, Mr Axelrod suggested, adding "This is the most unpredictable Republican race I have seen in my lifetime".
They therefore also believe - wishful thinking perhaps - that the Republican primary contest could last until June. That would indeed be a boon for Mr Obama, because of all the ground preparation being done by these, his very talented, very disciplined and very enthusiastic worker bees in Chicago's Prudential Building. It may still be months before the Republican challenger - Romney or someone else - will have time to build something remotely comparable.
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