nullification

英 [,nʌlɪfɪ'keɪʃən] 美[,nʌləfə'keʃən]

• n. 无效；废弃；取消；（美）州对联邦法令的拒绝执行或承认

1. the states'-rights doctrine that a state can refuse to recognize or to enforce a federal law passed by the United States Congress

2. the act of nullifying; making null and void; counteracting or overriding the effect or force of something