I went through this EXACT same issue in MN.
Read this thread:
http://www.ronpaulforums.com/showth...-display-campaign-sign-Take-THAT-you-FASCISTS!!
The reality is they CAN'T tell you it's illegal to have a political sign up within a certain date range of elections.
Put simply, a Real Estate company doesn't have a limitation on when they can put up a 'for sale' sign, right? So what makes them think they can tell you that you're not allowed a political sign?
It's called "Content Neutrality' and it means they are violating your 1st amendment rights. It's a slam dunk case. I actually got my city to CHANGE THE LAW.
PM me for more info if you need it. I'm trying to dig up more of the old info I had.
Chris