I don't like the calls for 'standing down' that have been thrown mostly from the right since at least Ferguson. Seems there was a bit of this in NY after the two policemen were assassinated. I understand the frustration, but really think the response to the attack on police is going to be more far reaching.
I think it's logical to surmise that many of the best that were considering law enforcement, be it via university or military will find themselves choosing not to go into public law enforcement. It's been happening for at least 10 years that I'm aware of. My son majored in law enforcement in university. Graduated with honors. Considered going into county or state police, decided instead to choose working in banking logistics and white collar crime. He was influenced by his uncle's advice, who finished 28 years in policing, retiring as Deputy Chief.
My brother had loved his profession, he taught part-time at Northwestern. He'd been the recruiter for his department for over 15 years, but saw that calibre of recruits was dwindling, mostly becasue the best couldn't reconcile the growing movement to reduce police discretion in arrests. Granted this particular department only hires university graduates or military with police experience, with an associate's degree. I can't imagine the problems facing less affluent municipalities and the choices they'll face.