# Supremacy Clause Article VI, clause 2: "This Constitution, and the Laws of the United States which shall be made in Pursuance thereof; and all Treaties made, or which shall be made, under the Authority of the United States, shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby, any Thing in the Constitution or Laws of any State to the Contrary notwithstanding." Three things follow, and each has been narrowed: - **Treaties are domestic law** — but only if self-executing. [[Medellín v. Texas]] (2008) held that a non-self-executing treaty creates no judicially enforceable rights until Congress implements it, and the Senate now attaches non-self-executing declarations as a matter of course. - **Treaties outrank state law** — the basis of [[Missouri v. Holland]] (1920) and of the *Avena* conflict in *Medellín*. - **Treaties do not outrank the Constitution** (*Reid v. Covert*, 1957), and do not outrank a **later** federal statute — the later-in-time rule means Congress can override a treaty domestically by simple majority while leaving the United States in breach internationally. The clause is also the engine of ordinary federal preemption doctrine, well beyond the treaty context. ## See also - [[How a Treaty Is Made and Ratified]] - [[Medellín v. Texas]] - [[Missouri v. Holland]] - [[Federalism]] ## The other half: federal law over state law The treaty cases are the Clause's exotic edge; its daily work is [[Federal Preemption]] — the rule that a valid federal statute displaces conflicting state law, whether Congress says so expressly, occupies a field, or the two cannot both be obeyed. That is the doctrine behind *McCulloch v. Maryland* (1819: a state cannot tax the national bank, "the power to tax involves the power to destroy"), behind the end of the [[Nullification]] theory that [[States' Rights]] advocates kept reviving, and behind the modern federalism wars in both directions. The second term has made it the sharpest instrument on both sides at once: the administration invokes it to override state [[Sanctuary Jurisdiction]] policies and state climate and consumer rules, while the states invoke it — in the [[Trump v. Illinois]] Guard cases and the tariff and election-order suits — to argue that an executive order is not a "Law of the United States made in Pursuance" of the Constitution and so binds no one. The Clause makes federal *law* supreme; it says nothing about federal *orders*, which is where most of the 2025–26 litigation lives. The [[Federalism Powers Crosswalk]] maps the field; [[Guaranteed Income Preemption]] is the state-level mirror, where legislatures preempt their own cities.