"Violence is down" in Baghdad and Washington, owing to similar, albeit differently scaled, programs to control the movement of populations from district to district, street to street. As a tactic, neighborhood cordons are clearly effective. Violence occurs when people with grievances gather together. So, prevent gatherings, or, barring that, identify oppositional grievants and keep them apart. Thing is, the grievances remain.
Consider Washington. That city's black underclass is systematically excluded from regular economic life. We say that the solution is "education," that if we give them all "vouchers" or what have you (the moderate-conservative position), or at least if we "invest in our schools" (the liberal position), then we will produce (the language is an industrial language) graduates (a newish category, implying inherent merit and, decreasingly, employability), who, because they are educated, acculturated, literate, numerate, and civically integrated, will family-by-family rescue the underclass from the mire of cyclical, generational poverty and disenfranchisement. Ha! Cities have neither the funds, the general wherewithal, or the inclination to repair their schools, and even if they could fancy up every building and put a Joe Clark in every front office, they'd still have the students to contend with. Education, such as it is, can only be effective if it's reciprocal, and neither side is interested in holding up its end of the bargain in failed urban districts. We aren't offering much of anything in any case. What work is there for an eighteen-year-old black guy with a high school diploma (or white guy, for that matter)? During the nineties it was possible (if you were a moron) to imagine that the "new economy," or the "information economy," or the "service economy," or whatever we were calling it on any given Monday, was going to produce a nation in which everyone was a white-collar worker, in which the transubstantiation of information (whatever that was) into currency would ultimately require that the entire working population occupy itself with management. At the time (if you weren't a moron) and in retrospect (if you were), it was and is clear that the managerial class must obviously remain a relatively small portion of the workforce, and that if you eradicate those enterprises that used to employ people, then there will be nothing and no one left to manage. In any case, entrance to the managerial class requires additional education, and though there are certainly odd cases of up-by-the-bootstrapsery, the cost of additional education, particularly baccalaureate education, is an insurmountable impediment for many. And again, even if that were not the case, then it would nevertheless remain true that graduating from college is no guarantor of employment, and to endure four years of economic hardship and academic struggle (since, let's be honest, your inner-city education stinks, even if you were at the top of your class, and you're always playing catch-up) in order to land a $30,000-a-year job with no prospects and additional hundreds of dollars deducted each month for health coverage barely superior to the emergency-room healthcare that serves as primary care for the poor is hardly a motivational model with great chances for success.
The persistence of violence in certain communities is rooted in the economy of poverty. (This is especially true in ulated cities, but almost any of the problems we ascribe to the black underclass are just as true for the rural white underclass. There's an astonishing amount of violence in rural and semi-rural America; because it isn't geographically concentrated, it isn't reported with the breathlessness of "22 killed in DC in the first 6 months of the year!") The principle economic activities of persistently impoverished communities are underground and black market activities. Narcotics, true, but also Real Estate, cars, appliances, CDs, clothing, food, etc. But because this is an "illegal" economy, its participants aren't able to use state authorities to mediate their disputes. Just as in proper states, though, there are codes of justice and punishment in underground communities. Violence is not merely random, and it isn't the only method of punishment, although corporal punishment is far more prevalent (as it was in pre-police, pre-modern cultures). There is in fact a panoply of punishments: economic punishments (fines); corporal punishments (beatings, etc.); punishments designed to "reform" offenders; capital punishment. The fact that our state predominantly chooses incarceration, a supposedly less brutal (questionably) and exceedingly more expensive sort of penalty is a difference of degree, not of kind. Much of the violence in inner-city communities flows directly from the necessity, or percieved necessity, to regulate and control the economy--in mimicry of the state itself. Cultural conservatives in particular will be quick to counter these arguments with anecdotes of random acts of violence, or retribution over cheating girlfriends, wandering boyfriends, disrespect, and so on. Of course, that sort of violence exists in every community, and it is only the fact that among the urban underclass it often exists alongside and in addition to a violent illegal-legal system that exaggerates its relative prevalence.
While violence in Iraq often has a more explicitly political component, nevertheless on the level of Baghdadi neighborhoods, say, much internecine fighting has to do with establishing which faction will control the microeconomies of this or that population; which gangs (tribes; ethnic groups; religious sects) will control which corners; who will extract protection money from whom; who will receive bribes, and who will pay them. Although I'm generally loath to even approach the orbit of the Incompentence argument, it would be dishonest not to admit that had the United States deposed Saddam Hussein without substantially destroying Iraq's infrastructure, and had the Iraqi economy swiftly been returned to something like regular operation, then the amount of a.) overt resistence and b.) civil conflict would be dramatically lower today. (We destroyed the infrastructure over the course of almost two decades, so this is idle speculation anyway.) A "functioning economy," which is to say an economy conducted within the purview of state taxation and regulation, has state-sponsored, state-created means of mediation, however imperfect, and if violence is to be done, it will be done by the "proper authorities." Since the regular Iraqi economy was destroyed by decades of economic santions and routine bombing, it was only natural--indeed, entirely predictable--that what did occur would occur.
The solutions, fortunately, are simple. Legalize drugs; legalize small economic activity across the board; and get the fuck out of Iraq, allowing them to legalize or illegalize whatever the fuck they choose.