The idea prevails with some, indeed it has expression in arguments at the bar, that we have in this country substantially two national governments; one to be maintained under the Constitution, with all its restrictions; the other to be maintained by Congress outside and independently of that instrument, by exercising such powers as other nations of the earth are accustomed to…. I take leave to say that, if the principles thus announced should ever receive the sanction of a majority of this court, a radical and mischievous change in our system will result. We will, in that event, pass from the era of constitutional liberty guarded and protected by a written constitution into an era of legislative absolutism…. It will be an evil day for American Liberty if the theory of a government outside the Supreme Law of the Land finds lodgment in our Constitutional Jurisprudence. No higher duty rests upon this court than to exert its full authority to prevent all violation of the principles of the Constitution. – Downes v. Bidwell, 182 U.S. 244 (1901) https://en.wikipedia.org/wiki/Downes_v._Bidwell