Comment Re:Under what authority? (Score 4, Informative) 298
In this case, you need a permit to use the park. Their permit said that they would not have this wanted fugitive perform. They violated the terms of their permit, so were shut down. This is pretty straightforward and they had to know this would happen - they probably wanted the publicity.
The restrictions in the permit were blatantly unconstitutional, therefore impermissable and unenforceable under US law. The city just set themselves up to be on the losing end of a lawsuit, if the promoter so chooses. If you don't believe, try washingtonpost.com and read the article and analysis. This is not a theoretical violation; the case law is well-settled, with the courts consistently banning these kinds of content-based restrictions on use of public space.