Sears, Roebuck and Co. v. Stiffel Co.
From Conservapedia
In Sears, Roebuck & Co. v. Stiffel Co., 376 U.S. 225, 231 (1964), the U.S. Supreme Court ruled that it is obvious that a State could not "extend the life of a patent beyond its expiration date."
Justice Hugo Black, who was generally opposed to most patent rights, wrote the opinion for a unanimous Court.
