这一宪法原则可追溯至19世纪中叶，当时最高法院推翻了威斯康星州最高法院一项抵制臭名昭著的1850年《逃亡奴隶法案》的裁定。
This is a constitutional principle that dates back to the mid-nineteenth century, when the Supreme Court overturned a Wisconsin Supreme Court ruling that nullified the abominable Fugitive Slave Act of 1850.