I don't think any lawyer would take that route, because the town is not being sued for applying a constitutional policy incorrectly. It is being sued for apply

I don't think any lawyer would take that route, because the town is not being sued for applying a constitutional policy incorrectly. It is being sued for applying an unconstitutional policy at all. Proving that he did, indeed, violate the town's statute by calling the mayor and police chief fascists is no victory if the statute itself is found to be patently unconstitutional, which it is.