https://en.m.wikipedia.org/wiki/List_of_mayors_of_the_50_lar...
It turns out the relationship between crime and population is non linear, and that nonlinearity is also true outside of the US and it's political context.
https://crimesciencejournal.biomedcentral.com/articles/10.11...
So, what you're seeing is bigger cities with higher per capita rates due to the underlying relationship between population density and crime. It also happens to be the case that in the US, urban areas strongly prefer Democratic mayors.
Quoting you: "There are far more cities with Dem mayors than Republican mayors, so comparing raw counts is pretty meaningless. (Similar to counting comparing total homicide instead of per capita.)"
Quoting me: "I did not compare raw counts, I compared per capita counts."
I did not learn anything I did not know before re-reading.
Here is the political affiliation of the city governments:
1. St. Louis, MO: Democrat
2. Detroit, MI: Democrat
3. Baltimore, MD: Democrat
4. Memphis, TN: Democrat
5. Little Rock, AR: Democrat
6. Milwaukee, WI: Democrat
7. Rockford, IL: Democrat
8. Cleveland, OH: Democrat
9. Stockton, CA: Democrat
10. Albuquerque, NM: Democrat
11. Springfield, MO: Independent
12. Indianapolis, IN: Democrat
13. Oakland, CA: Democrat
14. San Bernardino, CA: Democrat
15. Anchorage, AK: Independent
16. Nashville, TN: Democrat
17. Lansing, MI: Democrat
18. New Orleans, LA: Democrat
19. Minneapolis, MN: Democrat
20. Chicago, IL: Democrat
You seem to want to compare P(v|d) to P(v|r). We have little to no data for comparison because there are so few examples of cities with republican mayors. Those that exist are amongst the smaller American cities. This means you need to disentangle the effect of city size on violence rates from the effect of the mayor's party.
I repeat:
There are 10 Republican mayors amongst the 50 largest cities, and furthermore, these are heavily concentrated at the low end.
https://en.m.wikipedia.org/wiki/List_of_mayors_of_the_50_lar...
It turns out the relationship between crime and population is non linear, and that nonlinearity is also true outside of the US and it's political context.
https://crimesciencejournal.biomedcentral.com/articles/10.11...
So, what you're seeing is bigger cities with higher per capita rates due to the underlying relationship between population density and crime. It also happens to be the case that in the US, urban areas strongly prefer Democratic mayors.
The source provided does break it down per capita, and when done so, the 10 most violent cities in the US, measured per capita, are either democrat (9) or independent (1) controlled.