Treaty Supremacy Rule

The Treaty Supremacy Rule makes treaties made under the authority of the Constitution part of the supreme law of the land, while denying that a legislature may unilaterally cancel their obligations. Hamilton presents the rule as a consequence of treating treaties as agreements between parties: their mutual consent creates the bargain, and mutual consent is therefore required to alter or end it.

Constitutional Basis

The proposed Constitution’s Supremacy Clause places the Constitution, federal laws made pursuant to it, and treaties made by federal authority among the supreme laws of the land. Hamilton situates that provision alongside the Necessary and Proper Clause, which authorizes Congress to pass laws necessary and proper for carrying federal powers into execution. He argues that both clauses state implications inherent in creating a federal government with specified powers; omitting them would not change the government’s constitutional operation.

The limitation to laws made pursuant to the Constitution is essential to Hamilton’s account of federal supremacy. A law within the authority delegated to the Union must govern the states and their citizens, or the national government would amount only to a treaty dependent on the parties’ good faith. But an act outside those constitutional powers is usurpation, not supreme law. Supremacy therefore does not give the federal government unlimited authority over the states.

Treaties as Mutual Bargains

Hamilton answers the claim that treaties should be made only by legislators by distinguishing the legal force of an act from the identity of the body that makes it. Courts’ judgments and constitutionally issued commissions can bind those they concern without being acts of a legislature; executive and judicial acts of constitutional authority can likewise carry legal validity and obligation. The people may accordingly entrust treaty-making to a distinct constitutional arrangement rather than give the legislature every power of sovereignty that can bind citizens.

A separate objection accepts the proposed method of making treaties but denies that they should rank as supreme law. Its proponents would make treaties, like legislative acts, repealable at pleasure. Hamilton’s answer turns on the difference between a law enacted by one body and a treaty formed by two contracting parties. A legislature may amend or repeal its own laws, and treaty partners may alter or cancel their agreement—but neither party can unilaterally release itself from a bargain that binds both.

Scope and Consequences

On this reasoning, the Constitution does not newly enlarge the obligation of treaties. Their binding force already places them beyond the lawful reach of unilateral legislative acts; the proposed Constitution declares and secures that principle rather than inventing it. The rule protects the reciprocal character of agreements: the United States cannot claim that another nation remains bound while reserving to itself the option to disregard its own commitments whenever its legislature chooses.

The rule fits Hamilton’s broader distinction between legitimate national authority and encroachment. Federal measures derive their authority from the Constitution, and supremacy attaches to acts made pursuant to it. Treaty obligations, meanwhile, cannot be treated as ordinary domestic enactments that one party may revoke alone. The result is a defined form of national power: treaties bind as supreme law, but their mutual obligations cannot be rewritten unilaterally by the legislature.