This blog post is from a NYC Lawyer, and is a few years old. There are some updates in the comments. For the most part it does a great job of summing up the situation. Of course the situation just got a whole lot worse. It is by far a lot easier for politicians to pass unconstitutional law than it is to later repeal it.
If 'con' is the opposite of 'pro,' is 'congress' the opposite of 'progress?' - Philosoraptor