Don, large protests always require permits, mostly to insure public safety by giving the police dept a "heads up" to schedule more people that day. However, there's a big difference between getting a permit because a few thousand people might show up and requiring permits for more than 23 people of related political opinions to peacefully assemble in a public park at the same time when their presence does not require delegations to ensure public safety, nor in any way impedes the ability of the government or public safety officials to perform their duties, nor prevents other citizens from going about their business.

"Congress shall make no law respecting... the right of the people peaceably to assemble..."