Comment by nonameiguess

I think this highly depends on what you classify as change. I trained in policy science at one point and the MOVE incident was a huge case study we discussed to try and figure out at the bureaucrat level of city management how that situation came to be and how we could avoid it.

But the number one thing you learn from this kind of exercise is "political feasability" outweights all other pros and cons of a policy proposal you write up. We know how to prevent this kind of thing but we don't know how to sell it to voters. You see it right here on Hacker News. If it means you'll ever have to see a homeless person shit in public, everyone is immediately up in arms singing in unison "no please, give us stronger, better-armed police." If the Tiananmen Square protesters were blocking a popular commute route, half of America would be in favor of running them over themselves. No military intervention necessary.