It's simple folks: If it's being grown and distributed locally, and is legal under state law, the feds have no legal authority to seize plants, arrest growers or users, or otherwise hinder the legitimate use of marijuana for medical purposes. Yes, federal law trumps state law...but federal law can NOT cover areas that are not explicitly laid out in the constitution. That's why Prohibition REQUIRED a constitutional amendment.
It's exactly this sort of case the Feds have been avoiding for that very reason. They never dreamed that the climate could ever be as such that someone would have the balls to call them on it, or that a state's attorney general would SUPPORT medical pot.