MADISONCENTER FOR AMERICAN LEADERSHIP
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The Constitution,
connected.

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The constitutional text

Article I · Section 10

Select any highlighted phrase to understand what it means.

No State shall enter into any Treaty, Alliance, or Confederation; grant Letters of Marque and Reprisal; coin Money; emit Bills of Credit; make any Thing but gold and silver Coin a Tender in Payment of Debts; pass any Bill of Attainder, ex post facto Law, or Law impairing the Obligation of Contracts, or grant any Title of Nobility.

No State shall, without the Consent of the Congress, lay any Imposts or Duties on Imports or Exports, except what may be absolutely necessary for executing it’s inspection Laws: and the net Produce of all Duties and Imposts, laid by any State on Imports or Exports, shall be for the Use of the Treasury of the United States; and all such Laws shall be subject to the Revision and Controul of the Congress.

No State shall, without the Consent of Congress, lay any Duty of Tonnage, keep Troops, or Ships of War in time of Peace, enter into any Agreement or Compact with another State, or with a foreign Power, or engage in War, unless actually invaded, or in such imminent Danger as will not admit of delay.

Source: National Constitution Center edition. Original wording is preserved; commentary explains historical and superseded provisions.

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202 elements · 219 connections · One constitutional systemOpen the reader
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You don’t have to understand everything at once. One connection is a good beginning.

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Article I, Section 10, Clause 1g

States cannot rewrite criminal rules backward

Current text
ex post facto Law,

What it means

States may not enact prohibited ex post facto laws. The central protection is against retroactive criminal disadvantage, including making past conduct criminal or increasing punishment after the conduct occurred.

Historical setting

The Constitution repeats the prohibition because the federal and state governments have separate lawmaking powers. Federalist 44 treated such retrospective punishment as inconsistent with basic principles of justice.

What it does

The rule limits state criminal legislation independently of whether Congress approves or disapproves. Civil laws affecting earlier events require their own analysis rather than being automatically placed within this penal prohibition.

Debate & interpretation

Governments need capacity to change rules prospectively, but punishing people under rules unavailable when they acted undermines legal predictability. Hard cases arise when lawmakers describe a burdensome retroactive measure as preventive or civil rather than punitive.

A common misreading

Congressional consent cannot simply authorize a state to ignore this prohibition, which is stated without a consent exception.

Think it through

How would you explain the difference between lawful prospective reform and an unfair change to the legal consequences of yesterday’s conduct?

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Sources & further reading

Original Madison Center commentary. Explanations distinguish the text, historical context, and interpretive disagreements.

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