The U.S. Supreme Court case Truax v. Corrigan in 1921 revolved around the constitutionality of an Arizona law that required businesses with more than five employees to have at least 80% of their workforce be American citizens or individuals who sought citizenship. Mike Corrigan, a non-citizen cook employed by William Truax's restaurant, was fired due to this law and subsequently sued for wrongful termination. The court ruled in favor of Corrigan, stating that the Arizona statute violated both the Fourteenth Amendment’s Equal Protection Clause and employers' freedom-of-contract rights under common law principles incorporated into Due Process Clause jurisprudence. This landmark decision established important precedents regarding employment discrimination based on nationality and affirmed constitutional protections against such discriminatory laws.

In the dissenting opinion for Truax v. Corrigan, Justice Oliver Wendell Holmes Jr. argued that the Arizona law in question did not violate the Fourteenth Amendment's Equal Protection Clause as it was a reasonable regulation of business to protect workers' rights and prevent violence during labor disputes. He believed that states have broad powers to regulate businesses within their borders, including setting conditions on hiring practices if they serve a legitimate public interest such as promoting peace and order or protecting workers from unfair treatment by employers. Furthermore, he disagreed with the majority's view that this law violated an employer's freedom of contract because he saw no constitutional right to hire only non-union employees or fire employees for joining unions; instead, these were matters best left up to state legislatures rather than federal courts.