A recent example in the US was welfare reform. When states got waivers for time limits and work or training requirements for welfare recipients, they were so successful that federal welfare reform followed.
妥善实行一定地方分权的要求自有其道理，美国最高法院法官路易斯 • 布兰戴斯就有过将各州比作实验室的著名比喻。美国最近的一个例子便是福利改革。各州福利受领人不再受申报时限、工作以及培训要求的限制，结果令人满意，由此促成了联邦福利改革。