On a side note, the part Jenny had bolded in the article is very true. I'm not stating whether it is right or wrong, but ever since the New Deal and the Supreme Court of that era, Federal Law is the Supreme Law of the land. State's rights have taken a back seat to Federal Law... Just the way it is.
Preemption, however, has been around forever. Preemption is that Federal Law trumps state law, simply put.