Colorado has legalized marijuana. Undoubtedly, some of the out-of-staters who cross the border to purchase marijuana will take it back with them when they leave. This causes headaches for neighboring states that do not wish to legalize marijuana -- all of Colorado's neighboring states, to be exact.
That is what the Nebraska and Oklahoma v. Colorado lawsuit is about. Two states that barely border Colorado filed suit in the Supreme Court of the United States on Thursday. (Yay, a case of original state v. state jurisdiction that isn't a mind-numbingly boring water dispute!) They somehow hope that the Supreme Court will allow them to dictate what the law should be in a neighboring state by making a federalism argument -- a creative approach that seems unlikely to work.