Oh, believe me, I'm very happy living in this state. I think Jan Brewer is great, even though she vetoed the bill that would let CWP holders carry on University property...not sure why she did that.
Unenforceable was probably the wrong word. It could be enforced...the question is, would we (as in, the State of Arizona) really want to? Remember when Texas and a couple other states were going to pass bills that would make certain types of passenger screening illegal (meaning that TSA's normal procedures would be illegal)? I do, I was working for TSA at the time (it was a big mistake that I really do regret...I want nothing to do with that organization ever again...but back on topic). The Feds threatened to make the FAA cancel flights over it, stating that Texas wouldn't have security measures strong enough to ensure the safety of passengers. Texas backed down, because it would be detrimental to the Texas economy.
I commend our lawmakers and Governor for taking a stand against tyranny. But there's so much the Feds could do in response (even though I don't think they should have the ability to) that this really can't be anything more than a symbolic gesture. Though, I certainly do hope they make it more than just a symbol.
EDIT: By the way, something to keep in mind. The Civil War started as basically contention over states rights, and the 10th Amendment.