Louis Brandeis, a great Boston lawyer before ascending to the Supreme Court once eloquently and clearly presented the mechanism we have long had in place for doing something of the sort:

“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.” – New State Ice Co. v. Liebmann, 285 U.S. 262, 311, 52 S.Ct. 371, 386-387, (1932) (dissenting opinion of Brandeis, J.)

Back in 1932 a knuckle-dragging Supreme Court invalidated a law enacted by the State of Oklahoma that required  people who wanted to manufacture, distribute or sell ice obtain a license first.  In the dissent quoted above Justice Brandeis blazed a path that continues today – a path based on the clear recognition that states should be generally allowed to enact their own laws subject only to clear preemption by federal law.

This history has served the environment well.  Over the last 40 years the great advances in clean air, clean water and toxics reduction have come from the states – with the Federal Government following along. Sometimes these efforts have been states going it alone and sometimes it has been coordinated action by a group of states.  Two key examples of that kind of collective action are the way that automobile emissions regulations were developed by California and then adopted by a range of states, led by the New England states and the development of a Regional Greenhouse Gas Initiative by the states of the East Coast.

“The states as laboratories” does not have all the virtues of randomized trials like the experiments used in the pharmaceutical world but it does have the advantage of being very real.