The goal is to toe the line close enough that you make the other side over reach.
I'm curious how this dynamic will play out in Chicago for the G8/NATO conferences. Rahm Emmanuel has three discernible goals, which the protestors are well aware of:
1) Advance his own political standing on foreign policy grounds for his inevitable presidential run.
2) Advance Barack Obama's political standing during an election year
3) Advance his own political standing on law and order grounds for his inevitable presidential run.
As to number three, the Mayor probably has conflicting impulses. On one hand, he likely thinks punching hippies is a good way to show he is tough. On the other, the ghosts of 1968 loom large. It's a delicate balancing act. How far will the protestors push? Can Emmanuel restrain himself from over reaching?
I don't know the answer, and I certainly don't want people on either side hurt. But I do think this whole affair is completely self serving on the part of Rahm Emmanuel and I hope the protestors can find a way to make it a liability for him through peaceful civil disobedience.