How the Founders Defined “War”

The Framers viewed “war” as the state of hostilities between nations that legally altered the condition of peace — a public act requiring legislative authority.

Constitutional Convention (Aug. 17, 1787)

• The Committee draft had given Congress the power to “make war.”

  • Madison and Gerry moved to change it to “declare war” so the President could “repel sudden attacks” but not initiate hostilities.

  • Madison’s notes:

    “The Executive should be able to repel sudden attacks but not to commence war.” (Madison Notes, Aug. 17, 1787)

• The motion passed 8–1, showing clear intent: Congress alone could commence war, while the President could respond to invasion or attack.

“War” Defined in Founding Usage

• James Madison, Helvidius No. 1 (1793):

  “The power to declare war, including the power of judging the causes of war, is fully and exclusively vested in the legislature.”

  • He described “war” as any offensive operation, even without a formal declaration:

    “Those acts which involve the nation in war are legislative acts.”

• Thomas Jefferson, Letter to Madison (Apr. 27, 1793):

  “The Executive has no right to decide the question, whether there is or is not cause for declaring war.”

• Hamilton, Federalist No. 69:

  “The President cannot of himself declare war… he may, however, repel sudden attacks.”

• Thus, “war” meant any sustained offensive hostilities — not merely a formal declaration — requiring Congress’s consent.

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2. Which Hostilities Required Congressional Approval

The Founders drew a line between:

• Defensive actions (repelling invasion or sudden attacks): Executive power.

• Offensive or preemptive actions: Congressional power.

Examples in Early Practice

• Adams (1798) – Quasi-War with France: Congress passed statutes authorizing limited naval hostilities; Adams treated this as the legal basis, not an inherent executive power.

• Jefferson (1801–1805) – Barbary Pirates: Jefferson told Congress:

  “Unauthorized by the Constitution, without the sanction of Congress, to go beyond the line of defense, the moment our peace was threatened I sent a small squadron of frigates…” (Jefferson to Congress, Dec. 8, 1801).

  • Congress later passed formal authorizations for “acts of war.”

• Madison (1812) – War of 1812: He requested that Congress declare war, affirming the legislative prerogative.

Summary of Principle

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3. The Guarantee Clause and Presidential Defensive Power

Article IV, Section 4 — “Guarantee Clause”:

“The United States shall guarantee to every State in this Union a Republican Form of Government, and shall protect each of them against Invasion; and on Application of the Legislature, or of the Executive (when the Legislature cannot be convened), against domestic Violence.”

Interpretation at Founding

• The “United States” (acting through the national government) had a duty to protect states from external invasion or internal insurrection.

• This justified executive defensive action when time did not permit congressional deliberation.

• Hamilton, Federalist No. 74:

  “The direction of war implies the direction of the common strength… it is essential that it should be in the hands of one who can act with decision, activity, and dispatch.”

  • He referred to execution of defense, not initiation of war.

• Madison agreed that the Executive could act “to repel sudden attacks” — this included immediate invasion responses under the Guarantee Clause.

Key Distinction

• The Guarantee Clause gives the President executive duty and authority to act in defense of states under attack (or to suppress rebellion) without waiting for Congress.

• But offensive operations or punitive expeditions remained strictly within Congress’s exclusive power to declare war.

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4. The Founders’ Constitutional Balance

• Congress: Decides whether to change the legal state of peace to war.

• President: Executes war once declared; may act instantly to defend the nation or a state under invasion.

• Guarantee Clause: Confirms the President’s defensive power but not unilateral war-making power.

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Key Primary Sources

1. Madison’s Notes on the Constitutional Convention, Aug. 17, 1787.

2. Hamilton, Federalist No. 69 and 74.

3. Madison, Helvidius Letters (1793).

4. Jefferson, Message to Congress, Dec. 8, 1801.

5. War Powers Act of 1798 (Quasi-War with France).

6. U.S. Constitution, Art. I §8, Art. II §2, Art. IV §4.