 In 1886, when a Chinese laundry owner challenged the constitutionality of a San Francisco ordinance clearly designed to drive Chinese laundries out of business, the U.S. Supreme Court ruled in his favor, and in doing so, laid the theoretical foundation for modern equal protection constitutional law.See "Yick Wo v. Hopkins", 118 U.S. 356 (1886).Meanwhile, even with severe restrictions on Asian immigration, tensions between immigrant workers and native-born laborers persisted.