I think this is right [emphasis added]:
Let me float that the encampments are fundamentally about using government power against itself. By staking out a little ground and saying, "No, the government does not rule this space," it gets the mayors and police chiefs worked up. They deploy their increasingly militarized police officers to say, "Yes, the government does rule that space." Then, the protesters link arms and chant, and the riot cops come in with pepper spray and batons.
During the height of clashes between Occupy Oakland and police, I watched a livestream of protesters chanting, "Who are you protecting? Who are you protecting?" And kept watching as police launched tear gas into that crowd. The show of force was shocking. Now, that situation will pose a major political problem for Oakland’s mayor going forward.
Los Angeles Mayor Antonio Villaraigosa handled the eviction of Occupy LA with one thousand police officers. One thousand! There might have been less violence Tuesday night, but Occupy’s message (which was also Villaraigosa’s) still got sent: overwhelming force will be brought against political dissent.
So, why occupy? The point is not to hold a city park. The point is to dramatize the struggle of weak against strong, which is also the struggle of poor against rich. If the dominant theme of the occupations is, as Jay Rosen succinctly put it, "public policy favors the rich," then having the public police arrest the weak becomes a powerful metaphor for the message of the movement.