"It’s against the law for a Negro to kiss a white woman"

 Anti-miscegenation laws (laws banning interracial marriage) were introduced first in the 17th century in the original Thirteen Colonies that would become the United States. In many states cohabitation and sex between different races was also banned by law. In Texas, where this story is set, all non-whites were banned from marrying whites, in a law introduced in 1837. Such laws lasted in some states, including Texas, until as late as 1967, when they were ruled unconstitutional by the Supreme Court.