You can't separate them before the fact. That's why we have "punishment". DUI? Criminal punishment. Murderer? Criminal punishment. Etc, etc...
In a free society sometimes bad things are going to happen. You can't take all of a thing or right away in hopes of preventing it and still have freedom. That's what is happening in the US now and the result is an "unfree" society. Stick any label on it you want but the result is everything not specifically allowed by the state becomes a crime. In the interests of "safety" and security. Yet people are still never safe and secure, they just get a thin illusion.
If we want to keep freedom the only way to deal with the crazies is after the fact: Like that federal law against using a gun in the commission of a felony. It already exists. Why aren't we using it? Rob the local liquor store and get it plea bargained down to jay walking? It's still jay walking with a gun, federal crime. See you in 90 days for the jaywalking...and 20 years later for the federal felony.
Still wouldn't stop the real crazies because they are already planning on getting dead. Once they are in motion nothing will ever stop those people. We'd have to actually work on society and what creates them to start with and most people seem terrified of opening that can of worms. And politicians can't get as much mileage from trying to understand and fix the causes.
Do not go gentle into that good night.
rage, rage against the dying of the light!