Recognizing the principles of federalism, there is nothing to stop a state from allowing gaming within its borders for purposes it deems legitimate, nor anything to prevent the recognition of a state recognized tribe. However, since 1789 the U. S. Constitution included a grant by states to give exclusive power to Congress to regulate Indians and Indian tribal governments. (Article 1, section 8 clause 3 of the US Constitution) The Indian Gaming Regulatory Act (IGRA) both regulates and prohibits gaming on Indian lands for federally-recognized tribes, but does not address Indian groups that are not federally-recognized.