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.

• States and Military Affairs
• Duties of Tonnage
  • Overview of Duties of Tonnage
  • Historical Background on Duties of Tonnage
  • Determining Whether a Measure Qualifies as a Duty of Tonnage
  • Personal Property Taxes and Duties of Tonnage
• Compact Clause
  • Overview of Compact Clause
  • Historical Background on Compact Clause
  • Subject Matter of Compacts
  • Congressional Consent to Compacts
  • Requirement of Congressional Consent to Compacts
  • Legal Effect and Interpretation of Compacts