San Francisco is caught in a classic urban doom loop: tax rates and regulations rise, as do soft-on-crime policies. In response, businesses leave and police morale declines. That leads to jobs disappearing, tax revenue declining, and city services getting cut. Crime then goes up and the quality of life and quality of schools go down. Residents flee for greener pastures, especially conservatives and moderates. The remaining residents are disproportionately on the left. That gives Democrats a lock on the mayorship and city council. Which in turn spurs even higher tax rates, even more onerous regulations on businesses, and more soft-on-crime policies. The downward cycle continues. The result? Detroit.