The way I see it, America has a policing problem. And BLM shouldn't be protesting to defund the police, but to provide better funding. Normally I try to avoid coming across as the smug European who tells the Yanks what they're doing wrong, but policing is one of the few things I'm convinced is done better in Europe. And here's why: 18.000 police departments, 90% of which with 50 employees or less? That's a recipe for chaos.
We pay higher taxes over here in Western Europe and our municipalities have large budgets, yet still I'm certain my hometown could not properly 1. fund, 2. recruit, 3. train and 4. equip a police force to the highest of standards. There's a reason why in most countries law enforcement falls under the purview of higher subdivisions or even the central government: It's costly and requires thorough standardisation.
I'm told some American police departments provide as little as 18 weeks of training. I'm not surprised that officers this ill-prepared would be prone to over-reacting on streets more dangerous than our own. And yet European police agencies train their officers for 2 years and more, despite our crime rates being lower and gun violence being relatively uncommon. I can't help but see a link there.
These inadequacies could be solved by better funding. And since no one likes tax raises (particularly stateside), the other (and better) option would be to make policing a matter of the state. I just see no reason for local communities to run their own police departments, especially if they're too small or too poor to generate decent revenue. A reorganisation like that would also make policing more cost-effective (economies of scale).