It is one of the happy incidents of the federal system that a single courageous State may, if its citizens choose, serve as a laboratory; and try novel social and economic experiments without risk to the rest of the country.

Louis Brandeis (1856-1941) American lawyer, activist, Supreme Court Justice (1916-39)
New State Ice Co. v. Liebmann, 285 U.S. 311 (1932) [dissent]