Binding On States
Because Congress approves them, compacts can override conflicting state laws and are enforced by the U.S. Supreme Court, which hears disputes between states directly.
In plain English
When states team up by contract.
It's a contract between states, blessed by Congress, that locks in how they'll share something like a river or handle a common issue.
Simple example
The Rio Grande Compact of 1938 divides the river's water among Colorado, New Mexico, and Texas, setting delivery obligations each state must meet at specified points along the river.
Why it matters
What the term actually changes.
Shapes Daily Life
Compacts govern water supplies, transportation networks, and environmental rules that affect drinking water, farming, and energy across millions of residents.
Federalism Tension
Compacts let states craft regional solutions, but federal interests such as treaties or environmental laws can complicate or override state-negotiated terms.
How it works
The mechanics, in practice.
Negotiation And Consent
States draft and sign the agreement, then submit it to Congress for approval, which gives it federal legal status under the Compact Clause.
Allocation Formulas
Water compacts typically use measured flows, delivery points, and accounting rules to determine each state's share, often adjusted for drought or surplus conditions.
Dispute Resolution
When states disagree, they can sue one another directly in the U.S. Supreme Court, which may appoint a special master to recommend a ruling or settlement.
Related guide
How do states and the federal government share control over interstate rivers?
Interstate river water is governed by a layered system of state compacts, federal approval, and international treaties — a balance recently tested in the Rio Grande case.
Read the guide → Related issue brief
Should states retain primary control over interstate river water under federal compacts?
A long-running Rio Grande dispute has reignited debate over how much authority states versus the federal government should hold over shared rivers.
Read the brief →You’ve learned the term. Now vote.
Should states retain primary control over interstate river water under federal compacts?
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