

there is a fair amount of crossover between the cities (related to gang activity), specifically some of the national gangs which have alliances on the north side. The south side gangs in Milwaukee are much more territorial, though that's not new. The organized crime rivalries (amongst Sicilians) were quite prolific between the two World Wars, and into the 60s between the two cities.
Not that this is dispositive, but here are two rudimentary images of crime rates in Chicago (2.4mil) and Milwaukee (600k) respectively. Two very segregated cities with very similar homicide rates. The darker the blue, the safer (lower the rate of homicide, etc.). I've been out of the county and also federal court house for some time now, but I doubt things have changed much. There is significant gang activity in both of these cities, not news and I remember a map we had when I interned in the US Attorney's Office (working on HIDTA related cases, this is High Intensity Drug Trafficking Areas). The correlation between homicides and surprise surprise HIDT was totally in line. Such concentration. Meanwhile you could travel for miles through other parts of the city and you're in a different world altogether.
Milwaukee has always been heavily segregated, and I'm not just talking black or white. The city was founded in 1846, a city of immigrants, eastern europe, western europe, you name it. Germans were the largest immigrant force (still a German speaking school in the city), Irish, Poles, Serbs (Slavs), Italians. More Schmidts than Smiths was the joke. The city had and still does today, though less so, ethnic enclaves around the city. Catholic parishes are often known to be 'Italian' or 'Polish' or Hispanic churches. Blacks moved to Milwaukee in larger numbers during the post War period. Then the rust belt formed, suburbs boomed and inner city Milwaukee like many of its Midwest peers, started to deteriorate. It remains a majority minority city (I think its 40% black, 33% white, 20% Hispanic, 7% other)
Setting aside the obvious, among other things (poverty, lack of education, lack of opportunity, lack of family structure, presence of drugs), the one thing that bothers me is the lack of civic leadership. There's a reluctance of those outside these areas to stick their noses into the neighborhoods because then those in the high crime neighborhoods don't want hear it. Or they simply put their heads in the sand because it isn't their neighborhood. Meanwhile, those inside these neighborhoods, pounce on any sight of outsiders extending a hand, and (at least in Milwaukee) have forever maintained hostility towards the PD (whether that's justified, or not, it isn't helping matters. Obtaining cooperation in cases I worked was impossible. Nobody talks). The milquetoast history of Milwaukee mayors haven't exactly helped matters. They all walk on eggshells.
In many respects it is a wonderful and beautiful city with so many positive qualities but it sure has some serious problems. This post isn't designed to incite or push one button or another, just trying to highlight some of the dynamics.