In O'Conor v. Texas, the U.S Supreme Court ruled on a dispute over land ownership in Texas. The plaintiff, M.F. O'Conor, claimed that he had purchased the land from its original owners who were Mexican citizens before 1848 when Mexico ceded territory to the United States following the Mexican-American War. However, under an 1854 law passed by Texas legislature which required all claims for lands granted by Spain or Mexico to be filed within a certain period of time (which Mr.O’Conor failed to do), his claim was denied and deemed invalid. The case reached the Supreme Court after several rounds of litigation in lower courts where Mr.O’Conor's claim was repeatedly dismissed due to non-compliance with this law. In its decision, however, the Supreme Court held that while states have broad power over property rights within their borders; they cannot pass laws that infringe upon vested rights guaranteed under treaties between nations - such as those recognized through Treaty of Guadalupe Hidalgo which ended Mexican-American war. Therefore it concluded that since Mr.O’Connor’s purchase predated this treaty and subsequent state legislation requiring registration of foreign grants; his title could not be invalidated based on failure to comply with latter requirement.

In the dissenting opinion for O'Conor v. Texas, it was argued that the majority's decision to uphold a tax on interstate commerce conflicted with previous rulings of the Court and violated principles of federalism. The dissent contended that by allowing Texas to impose a tax on goods transported from other states, the majority effectively allowed individual states to regulate interstate commerce - an authority constitutionally reserved for Congress. This interpretation could potentially lead to protectionist policies and trade wars between states, undermining national unity and economic integration. Furthermore, it was suggested that this ruling would create legal uncertainty as businesses engaged in interstate commerce would have difficulty predicting their potential tax liabilities across different jurisdictions.