"About a century and a half ago ... California set out to seal
its borders against unwelcome arrivals. As today, the state’s
immigration code met legal challenges, and the resulting Supreme Court
decision helped firmly establish federal authority over immigration. One
critical case involved 22 Chinese women who were identified by a
California official as “lewd”—i.e., prostitutes—and barred from entering
the United States under state law. Its story shows how 19th-century Supreme Court justices came to disapprove mightily of state efforts to regulate immigration." - Paul A. Kramer, Slate, Apr. 23, 2012.