'There are two Americas - separate, unequal, and no longer even acknowledging each other except on the barest cultural terms. In the one nation, new millionaires are minted every day. In the other, human beings no longer necessary to our economy, to our society, are being devalued and destroyed'

Baltimore - it's been an ordinary week in Maryland's largest city. The August heat broke and one can nearly sleep with a window open; the Orioles are again down in the cellar in the American League East; the city murder rate is a bit behind last year's blood-letting, and if it holds into the fall, politicians and police commanders will compete to claim credit.

The stories in the Baltimore Sun remain fixed on the surface, each of them premised on the givens: schools will open next week and provide more or less the same inferior education as previous years; Johns Hopkins is building its biotech park expansion where the East Baltimore ghetto used to be and the ghetto is migrating due east and north-east; the biotech park will be great for white folk with college degrees, for those with union cards, the factories are still closed and the port is still losing cargo to Norfolk; a shooting here, a cutting there ...

All in all, an unremarkable summer.

Save for one lonely headline the other day - something that genuinely intrigues. It's a curious item - a draft report by a local non-profit foundation, a simple statistical study of the difference between Baltimore criminal juries and those of the surrounding, suburban counties.

It seems that in Baltimore, one of the most violent cities in America, jurors are far more reluctant to convict criminal defendants than in the suburban enclaves that ring the city.

The report upset the city's chief prosecutor; she thought its conclusions "politically divisive" and asked the foundation to either amend the draft study or kill it entirely. The press mocked her for this, of course, and rightly so, while on the radio here, white talk-show hosts had fun speculating about why city jurors - read "black people" - won't do their civic duty when it is, in fact, their communities that are so overwhelmed by crime.

Everyone had something to say for a day or two, and of course, after that brief span of time, the entire issue disappeared into the glowing mediafest that was Michael Phelps and his remarkable collection of gold medals. Phelps is from Baltimore, by the way. As he is not wrapped in crime-scene tape, hampered by a budget shortfall or unable to raise his standardised test scores to the national average, we claim the great Olympian with considerable pride. The boy can swim, yes he can.

In any event, the story about the reluctant city juries slipped quickly below the waves in the Beijing pool without anyone ever seriously inquiring into the why of it, much less attempting to do any actual reporting on the matter.

Anomaly noted. Half-assed speculation offered. On to new business.

But here's the thing of which we can all be certain, the thing that fuels all the dramatic arcs of The Wire, in fact: the why is the only thing that actually matters. The who, the what, the when, the where, even the how - every other building block in which journalists and policy planners and political leaders routinely trade - amount to nothing beyond the filler, interchangeable with the facts flung a year ago, a year from now and decades hence.

The why is it. The why is what makes journalism an adult game. The why is what makes policy coherent and useful. The why is what transforms bureaucrats and foot soldiers and political leaders into viable instruments of rational and affirmative change. The why is everything and without it, the very suggestion of human progress becomes a cosmic joke.

And in the American city, at the millennium, the why has ceased to exist.

When I read reviews and commentary on The Wire in the British press, I am usually moved to a peculiar and conflicted place. I'm gratified by the incredible amount of verbiage accorded our little drama and I'm delighted to have the fundamental ideas and arguments of the piece discussed seriously.

But at the same time, I'm acutely aware that our dystopian depiction of Baltimore has more appeal the farther one travels from America. The Wire is, of course, dissent of a kind and it is true that there are many of my countrymen who are in fundamental disagreement with the manner in which the nation is being governed and managed. But somehow, it sounds better to my ear when it's my own people talking trash and calling our problems out.

At the same time, it's not just a question of standing, but of nuance as well. I get that we've been the bull in the china shop internationally, that we've been arrogant and tone-deaf in so many arenas for so many years, and now, with the margins of the American empire being pressed, everyone is ready to embrace the requisite number of I-told-you-so moments. Fair enough. We had it coming. But the emotion in all of that sometimes leads the overseas commentary about Baltimore and The Wire toward something that I don't recognise as accurate.

Baltimore is not the inner circle of hell. It is not entirely devoured by a drug economy that serves as its last viable industry. It is not a place in which gangsters routinely fire clip after clip, spraying the streets in daylight ambushes. It is not unlivable, or devoid of humanity, or a reservoir of unmitigated human despair.

I live in Baltimore, in a neighbourhood that is none of these things. I am vested in the city and its future and I can drive you to places in this city that would transform even the most devout Wire fan into a fat, happy tourist. Baltimore's charms are no less plentiful than most American cities.

And yet there are places in Baltimore where The Wire is not at all hyperbole, where all of the depicted tragedy and waste and dysfunction are fixed, certain and constant. And that place is, I might add, about 20 blocks from where I live.

That is the context of The Wire and that is the only context in which Baltimore - and by reasonable extension, urban America - can be fairly regarded. There are two Americas - separate, unequal, and no longer even acknowledging each other except on the barest cultural terms. In the one nation, new millionaires are minted every day. In the other, human beings no longer necessary to our economy, to our society, are being devalued and destroyed. Both things are true, and one gets a sense, reading the distant reaction to The Wire, that Europeans are far more ready to be convinced by one vision than the other.

I used to quote Churchill as declaring that a first-rate mind was one that could maintain two opposing ideas at the same time. It certainly sounded Churchillian to me until someone better read pointed out that this notable quote is by F Scott Fitzgerald.

At first this disappoints, because the quote, to me, seems to argue for political nuance, for subtlety and precision in state affairs. For a long while, the literary origin of the credo made no sense.

But then, The Wire.

As with Fitzgerald, we were selling story only. And at all points, when filming our drama, we understood that we were arguing the case of one America to the other. We were not saying everything, showing everything. We focused on the urban dynamic of drugs, crime and race. We argued the fraud of the drug war and offered an elegy for the death of union labour and the working class. We ruminated on the political infrastructure and its inability to reform. We picked a fight over the decline of public education and the lie behind our national claim to equality of opportunity. And lastly, we suggested that in the end, no one in our media culture is paying attention or asking hard questions.

We did not contemplate immigration. We largely ignored sex-based discrimination, feminism and gender issues. We spoke not a word about the pyramid scheme that is the mortgage crisis, or the diminishing consumer class, or the time bomb that all of our China-bought debt might prove to be. Nor did we glory in the healthy sectors of the American economy, in the growth industries of the information age. We did not embrace Brooklyn Heights and West Los Angeles, Silicon Valley and Marin County. Hell, we didn't even rest for more than a day or two in Roland Park or Mount Washington or Towson - those Baltimore neighbourhoods that define a viable, monied America. We spoke to the other part of town, the forgotten place, the one they don't tell many stories about, at least not in the medium of entertainment television. It was a story rooted in truth, but it wasn't the only story or the only truth. Who, but a second-rate mind, would claim otherwise?

Yet in my country, they actually argue the point. While British audiences might believe The Wire to represent more than it does, Americans - many of them, at least - are quick to argue that it doesn't represent everything and is therefore, somehow, not representative of anything at all.

Was the Wire myopic? Should it have been allowed to dwell for five seasons on that in America which is broken and brutal? Was it not obliged, as an act of journalistic equanimity, if not dramatic power, to display portions of the America where human lives are not marginalised and discarded?

Well, there are about 350 television shows about the affluent America, the comfortable America, the viable and cohesive nation where everyone gets what they want if they either work hard or know someone or have a pretty face or cheat like hell. That America is available every night, on every channel in the Comcast package.

For a brief time, there was one television drama about the other America.

Are we really going to debate whether it was one too many?

Which brings us back to this week in Baltimore and that jury report, the one that everyone had something to say about, but no one actually bothered to analyse. The draft study, which tracked jury trials in Baltimore over a one-year period from July 2005, found that jurors in surrounding, predominantly white suburban counties were 30 times more likely to convict defendants of the most serious charge. Overall in the surrounding counties, the acquittal rate was 27%. In the city, it was 43%. And the disinclination of Baltimore juries to convict drug defendants on serious charges was even more pronounced, according to the Baltimore Sun.

The Sun's coverage indicated that the report's author had speculated vaguely as to "population characteristics and socioeconomic factors" being relevant to the statistical variance. The Sun itself provided no additional analysis, reportage, thought or speculation as to why city juries behave as they do.

Again, the why of the thing. The only part that really matters.

Because in my city, we have fought the drug war to the very end of the line, with sergeants becoming lieutenants and majors becoming colonels and city mayors becoming state governors. We have done so for decades, one day into the next, one administration after another, each claiming progress and measuring such in arrest rates, drug seizures, crime stats. And no one asks: why?

No one asks why, with all the arrests and seizures, the availability and purity of narcotics and cocaine has actually increased over the past three decades. No one asks why, with all the law enforcement committed, whole tracts of the city have nonetheless degenerated into free-fire war zones. No one asks why police commanders are routinely able to reduce the rates of robbery, or rape, or assault significantly in any time period prior to an election, while the murder rate - in which the victim can't be obscured or clerically "unfounded" - stays as high as ever. And now, this week, no one asks why men and women from Baltimore, upon being given a chance to strike a blow against disorder and mayhem by convicting those charged criminally, would shirk their responsibility.

Well, here it is, plain as day...

In order to elect Baltimore's mayor as Maryland's governor, crime had to go down. And when that mayor was unable to do so legitimately, through a meaningful deterrent, his police officials did not merely go about cooking their statistics, making robberies and assaults disappear by corrupting the reporting of such incidents, they resorted to something far more disturbing.

For the last years of his administration, Mayor Martin O'Malley ordered the mass arrests of citizens in every struggling Baltimore neighbourhood, from eastside to west. More than 100,000 bodies were dragged to Central Booking in a single year - record rates of arrest for a city with fewer than 700,000 residents. Corner boys, touts, drug slingers, petty criminals - yes, they went in the wagons.

But school teachers, city workers, shopkeepers, delivery boys - they too were jacked up, cuffed and hauled down to Eager Street - hundreds of them a night on the weekends. Some were charged, but few were prosecuted. And in 25,000 such cases, they were later freed from the detention facility without ever going to court; no charges were proffered because, well, no crime had been committed.

I wasn't arrested. Nor was Ed Burns or Dominic West or Aidan Gillen. Nor were my neighbours or the Baltimore Sun's editors or the members of the Maryland Club. But then, we're all white. Among the black members of my cast and crew, it was often impossible to drive from the film set to home at night without being stopped - and in some cases detained or arrested - on nonexistent probable cause and nonexistent charges. The crackdown came wholly in black neighbourhoods and it landed wholly on the backs of black citizens.

And now, just a few years later, comes this document that causes the state's attorney to deny the obvious and leaves everyone else wondering weakly and vaguely as to the why of it. Is it so hard to understand that the same people who had their civil rights cleanly dispatched, who spent nights in jail because police officers lied on them and dragged them off without charge - that these people might be inclined to disbelieve the word of law enforcement in any future criminal case?

In places like West Baltimore, the drug war destroyed every last thing that the drugs themselves left standing - including the credibility of the police deterrent. To elect one man to higher office, an entire city alienated its citizenry and destroyed its juror pool.

Mayor O'Malley is now Governor O'Malley. The police commanders have all been promoted. A daily newspaper that had no stomach for addressing the why a decade ago when it had 400 editors and reporters, a newspaper more consumed with prize submissions and gotcha stories than with complex analysis of its city's problems, now has 220 bodies in its newsroom and is even less capable of the task. And nothing, of course, changes.

Yes, such a scenario is grist for The Wire. We could have easily built half a season out of the collapse of the Baltimore jury pool and the inability of city prosecutors to bring cases into court.

Yet there is also something appalling in the suggestion that a television drama - a presumed entertainment - might be a focal point for a discussion of what has gone wrong in urban America, for why we have become a society that no longer even recognises the depth of our problems, much less works to solve any of them.

But where else is the why even being argued any more? Not in the stunted political discourse of an American election cycle, not in an eviscerated, self-absorbed press, not in any construct to which the empowered America, the comfortable and comforted America, gives its limited attention. To know why city juries won't participate in the drug war any more, to know why they have opted out of our collective dysfunction, you'd have to travel to the other America - to West Fayette Street or Park Heights Avenue or East Madison Street or any other of the forgotten places. And, well, as has already been said, we are separate nations at this point. Few of us ever cross the frontier to hear voices different from our own. ·

· A newspaperman for 13 years, David Simon is the author of Homicide: A Year On The Killing Streets, published in the UK by Canongate, as well as an executive producer and writer of HBO's The Wire.