In the 1913 U.S. Supreme Court case John, Guardian v. Paullin, the court was asked to determine whether a state law in Oregon that required all foreign corporations doing business within its borders to appoint an agent who lived in-state for service of process violated the Fourteenth Amendment's Equal Protection Clause. The plaintiff argued that this requirement unfairly discriminated against out-of-state businesses and thus infringed upon their constitutional rights. However, the Supreme Court disagreed with this argument and upheld Oregon's law as constitutional. The court reasoned that states have broad powers under their police authority to regulate commerce within their boundaries and protect local interests from potential harm caused by foreign corporations operating there. It further held that requiring these companies to maintain an in-state representative did not impose any undue burden on them or violate equal protection principles because it applied equally to all such entities regardless of where they were incorporated or headquartered. Therefore, according to Justice Holmes' opinion for a unanimous court, while states cannot discriminate against interstate commerce per se or create unnecessary barriers thereto without violating federal constitution protections; they can enact reasonable regulations like those at issue here designed primarily for administrative convenience and efficiency purposes rather than discriminatory intent.

In the dissenting opinion for John, Guardian v. Paullin, Justice Holmes disagreed with the majority's decision to reverse a lower court ruling that had awarded damages to an injured child. He argued that it was not unreasonable for the jury in the original trial to find negligence on part of defendant and award compensation accordingly. According to him, there were sufficient grounds for such a finding based on evidence presented at trial including testimony about how fast defendant’s car was moving when it hit plaintiff’s wagon and caused injury. The justice also noted that while some might argue this case involved questions of state law beyond Supreme Court's purview, he believed federal courts should be able to review decisions involving constitutional rights even if they touch upon matters typically left up to states.