And the lovely Congress effectively making research into the causes and effective remedies for gun crime impossible through barring research. So we don’t have reliable measures, or any studies of academic rigor to see what possible options are effective at reducing gun crime.
And you are spot on about the variance in gun laws. Indiana has some of the least restrictive on the books, and that absolutely has an impact on the efficacy of anything in Chicago. Which points to the obvious fact that anything would require some form of Federal level policy.
And, yeah, things are complicated. The models are very noisy, and there has been a 20 year down swing, with localized upswings in the last 2-3 years. But all that aside would you accept the notion that easier access to guns increases gun ownership? At a purely baseline level the more convenient, easier, and also therefore likely cheaper, guns are to get, the more likely they are to enter circulation? So even though Indiana has, effectively, useless gun control the very fact it was another state (directly bordering the city at points though it may) would have some supressive effect? But we ultimately don’t know, because no federal agencies, or group that receives federal funds (thus any universities), can directly study this.
So, yeah, its hard to state what effect the Supreme Court case had. And the effects may not be uniform. It is plausible to think the ruling would make guns somewhat easier (though as noted it wasn’t a very hard task before), therefore have some effect that correlates with increased gun violence. Because Heller was expanded by McDonald, as Chicago had fought the ruling by saying it was only applied to Federal Enclaves. And post McDonald we see the gun crime reductions that Chicago had seen for 20 years taper off, then reverse dramatically. Is it possible there is more at play? Almost certainly! Is it possible those rulings created a feedback with those other factors to increase gun violence? I find this likely.
And there is a lot more than simply gun access to violent crimes, obviously. concentrated and generational poverty is one of the strongest factors, and pretty obvious too. Broken Windows Policing, lack of opportunities in areas increasing recidivism, and a while host of other issues have huge effects, and are why even though DC’s strict gun laws existed, it had higher crime rates than Wyoming or Indiana. Things don’t exist in a vacuum.
Gun control, access, etc. are but one piece in a puzzle, but an important one.