Increasingly, when we talk about gun violence in this country we also talk about mental illness. In many ways, this is not surprising: A number of instances of gun violence are committed by those with untreated, or undiscovered, mental disorders. This has lately led many politicians to place the blame for incidents of gun violence squarely on the lack of resources available for those suffering from mental illness. "It's a mental illness problem," Donald Trump recently declared on "Meet the Press" on NBC. "Guns, no guns, doesn't matter.