I live in France, where we've just had terrorist attacks, and I'm afraid we'll meet the same pattern, 15 years later than USA:
- People want the police to do its job (securing the streets, which goes from checking car insurances to being detectives on terrorism),
- So they vote for more police,
- The police doesn't do much more than assaulting easy targets, picking up girls who come to lodge a charge (true story), and walk on cyclist lanes (not much traffic enforcement because it's unpopular and not much detective work because it's risky),
- So people vote even more right-wing,
- Police has more powers, but still doesn't do its job much, and assaults even more weak people,
- Then we get people who kill police (like in Dallas) or burn police cars (like in Paris) because they're abusing their power.
Already, President Hollande made the same talk and took the same path on 13th Nov 2015 as Bush on 11th Sept 2001, so I'm a little afraid there's a trend were.
Now what societal changes could happen that would disrupt a race to the bottom of police brutality, like in USA?