The CNN Grill is up and running, even though it’s only Sunday morning. The Grill’s a faux restaurant that the fading network sets up in each convention city. C-Span, the congressional channel, has the same deal down the road, as does MSNBC, which has a sort of weird shop/bar/venue arrangement, like some sort of weird cult, which I guess …

What’s weird about these places is the lengths they go to. It’s more than a banner and a card in the window — whole bars are taken over, their permanent signage changed, so that, coming down the street, it looks like the place has been there forever — forever, in a US city, meaning about eight years. Two in three people in the city centre have a Democrats convention pass, everyone strutting around proud to be important, the huge laminated pass flapping on paunches and lady flop-fat.

The vibe’s different here at the Democrats Convention in Charlotte, compared to Tampa. The people are black, white, Latino, young and scruffy or working-class — what the media calls middle-class — tougher-skinned, blotchy, in chain-store shirts, and baseball caps. Dressed up for the event, but not that far up. And, among them, there’s the sharks and pros, in sharp suits, hustling through the crowd, blurting into androids. In Tampa, it was brown people serving white people, the GOP’s roll-call of minority achievers on the stage (and nowhere in the crowd) not withstanding.

But the city itself is pure Jeffrey Smart, a downtown replaced by block-by-block multistorey car parks, malls and faceless hotels. It’s another city to mourn, another urban suicide, barely a row of shops, or a building older than 1982, nothing to say, in stone and brick, that people lived, loved and died here for three centuries. Even the crowds pouring through it today cannot humanise it. On an average Tuesday morning, with its empty whistling streets, it must be like death itself.

Americans do not realise that, in hollowing out the city, the focus of civilisation since 4000BC, the place of the random embodied encounter, they have hollowed themselves out, their own capacity for sociality. Deprived of a real context, the need for such sociality then takes on ideal forms — nation, religion, the pseudo-community of the sitcom (how much of a clue is it that the most significant example of that genre was called, simply, generically, Friends?).

Dissident art sometimes make this loss visible — The Tree of Life, Terrence Malick’s flawed recent masterwork, has an architect, an author of silver, mirrored towers, reflecting back on a grounded, single-storey childhood in a small Texas city, Anne Tyler’s Baltimore novels catch it in the background — but in general it has happened too slow, too gradually for anyone to shriek in horror at what happened (with exceptions: Chrissie Hynde’s song My City was Gone is about the closest it gets).

You could say this is background. It is to Americans, but it’s the context in which they live, and anyone not from there cannot help but note it, if they are attentive to anything more than political gossip. We’ve all had our societies remade by the forces of new forms of capital over the past 40 years, but even a glass-cavernous wasteland like downtown Sydney is Paris in the summer, when it sizzles, compared to cities such as Charlotte, or Atlanta, or Buffalo, or …

You see it when it is disrupted — as it was about 1pm today, when the “March on Wall Street South” came down the main street. Charlotte is the largest concentration of financial capital south of NY, and the coalition of 90 different groups was hoping to use the venue as a focus. Ten thousand marchers were promised. There were fewer than 1000, dwarfed by concrete canyons.

The city is good for both conventioneers, and for protesters. The state went for Obama in 2008, by barely 20,000 votes — a get that surprised Republicans and Democrats, and that has made Mitt Romney’s task all the more difficult. Polls indicate that the GOP will take it back, but it’s still line-ball, and if they want it, they will have to spend a lot of time and money, that could otherwise go to Ohio and Florida.

Not only is it a centre of capital, it is a centre of black capital, with 35% African-American population in a somewhat better position than in South Carolina, a confederate backwater. It is perfect for the image Barack Obama wants to project — one of confidence and resistance, of  a connection to new formations of capital, but also to the oppressed and beaten down.

He is going to need it. He is going to need to project something, a dream in this empty city, to thoroughly surround the Republican vision of America as outlined in the Tampa convention. That may not be as difficult as it looks — as the GOP convention recedes in time, it is receding in memory faster, with little of Romney’s speech hanging around in the ether.

There is only crazy Clint’s empty chair speech, discussion of which has entirely upstaged the candidate himself, though to be fair a Mr Blowy in a car yard could have done that. By Sunday morning, three days after the wrap-up, a significant Romney bounce had failed to emerge — the Mittster was four points ahead in one poll, but it was Rasmussen, a notoriously Republican-skewed outfit (they rely on landlines. Remember landlines? Your angry grandfather does.) A Reuters/Ipsos poll out today had them tied, which is how it has been for a month.

That is a pathetic result to come out of a convention, and it offers a real opportunity for Obama to retake the debate, and put the Republicans on the defensive, where they might stay. He has a formidable task, because his achievements have been so middling, in the eyes of a public who perpetually demand a “return to greatness”. The pundits have been doubtful for months, but we have been here before, and so in this cavernous concrete dystopia, festooned with cops, we return to our old and reliable NUBO. NUBO. Never Underestimate Barack Obama …