As the Supreme Court observed in Fong Yue Ting, an 1892 case in which several Chinese nationals challenged an 1888 congressional prohibition on the reentry into the US of Chinese laborers who had left the country: "It is an accepted maxim of international law, that every sovereign nation has the power, as inherent in sovereignty, and essential to self-preservation, to forbid the entrance of foreigners within its dominions, or to admit them only in such cases and upon such conditions as it may see fit to prescribe." One hardly has to go back to Chinese labor cases from the 19th century to find the court recognizing the essential nature of borders as an incident of national sovereignty consigned to the political branches.