Today In Wyoming's History: December 18:
2014. Nebraska and Oklahoma filed a petition with the United States Supreme Court seeking to have leave to sue Colorado on a Constitutional basis.regarding Colorado's state legalization of marijuana. The basis of their argument is that Colorado's action violates the United States Constitution by ignoring the supremacy nature of Federal provisions banning marijuana.
While an interesting argument, my guess is that this will fail, as the Colorado action, while flying in the face of Federal law, does exist in an atmosphere in which the Federal government has ceased enforcing the law itself.