Are you suggesting that “urban hubs” and “immigration tension” are code words for “black people” and “slavery”? Because I regret to inform you that when New York City established the first US police department in 1845 (per britanica) the “immigration tension” at the time would have been the influx of Irish immigrants. And while Cincinnati had indeed had a white on black race riot in 1841, when it established its own police department in 1852 the anti-catholic / anti-German immigrant riots in 1853 and 1855 were the more contemporary “immigration tensions” I was referring to. Boston too when it founded its police department in 1854 was in the middle of a surge of Irish immigrants. Certainly these northern state city centers weren’t simply giving uniforms and badges to “slave patrols” when they founded their police forces, regardless of what other racial tensions may or may not have played a hand in the demands for a police force.

All of which is to say if you recall your American history, we have a long and storied tradition of hating on our immigrant populations and having conflicts with them. Yes white vs black was a problem at the time. And so was “white vs Irish” and “white vs German”. Our history is littered with racial tensions across just about every set of ethnic lines you could care to draw.

Edit:

I note now that my britanica link in my first post was the wrong one, this would be the more appropriate for the topic at hand: https://www.britannica.com/topic/police/Early-police-in-the-...