Chicago was run by Richard Daly 2 for 20 years during the Guliani era. I’m not sure what a no-nonsense mayor is but Daly resolved a dispute over an airport by having the runway jack hammered over night in the middle of negotiations.

During the 80s CPD ran a torture warehouse. They are currently operating under court direction for their mass use of pre textual traffic stops.

I’m not buying your “just so” story about mayors or hard nosed policing being the difference.