I think you would find that they would make far fewer illegal mistakes if they actually had to deal with the consequences of those mistakes.
Qualified Immunity didn't exist as a concept until the 1960s, and it was put in place to shield policemen enacting racist policies and corrupt cronies of Nixon.
As it currently stands the police already do almost nothing. Any kind of push back or critique of the police leads to inaction by the union. Meaning, police twiddle their thumbs and take your tax money because they can. It's a very effective technique from them to get what they want, because ultimately we need them and we can't actually force them to work.
I agree with voidfunc. A lot of what police do could be offloaded to other occupations. A lot of needless deaths could be prevented if there were more rungs on the escalation ladder between "do nothing" and "folks with guns show up". Like the same vibe as firefighters and EMS but just like for mild social disruption.
