The maximum hours question returned to the United States Supreme Court three years later in Muller v. Oregon with this twist--Oregon's maximum hour statute applied only to women. To shore up its case, Oregon hired Brandeis who wrote the first "Brandeis brief" , which supplements the bare bones of legal theory with detailed sociological and scientific argumentation.
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Of course Brandeis never imaged [sic] that this legislation would do anything more than reduce the hours of women workers, while everything else stayed the same. He won unanimously in the Supreme Court. But did it come as a rude shock to Brandeis that the women Oregon protected were promptly sacked by their employer Curt Muller, who replaced them with Chinese men. Modern feminists are rightly alert to the insidious effect of women-only laws, which would, happily, be struck down as unconstitutional today. Why aren't they libertarians?