In 1932 the Supreme Court struck down an Oklahoma law that required a license to sell ice. Justice Louis Brandeis dissented. “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.”
Americans now speak of the states as “laboratories of democracy,” an idea that takes its name from this dissent. One example is the health care law Massachusetts passed in 2006. It became the model for the federal Affordable Care Act.