Under U.S. law and international norms, the U.S. is not strictly required to declare war before conducting military strikes—especially if the operation is framed as:
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Self-defense (under Article 51 of the UN Charter),
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A limited military action, or
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A response to attacks on U.S. personnel or allies.
1. U.S. Constitutional Law
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Congress has the sole power to declare war (Article I, Section 8).
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But presidents often authorize military action without a formal declaration of war, citing:
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The War Powers Resolution of 1973, which allows the President to use force for up to 60 days (plus 30-day withdrawal) without Congressional approval.
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Existing Authorizations for Use of Military Force (AUMFs), such as the 2001 or 2002 AUMFs, which are sometimes stretched to justify strikes.
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The War Powers Resolution of 1973, which allows the President to use force for up to 60 days (plus 30-day withdrawal) without Congressional approval.
2. Recent Practice
The U.S. has not declared war since World War II. All subsequent conflicts—including:-
Vietnam,
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Kosovo,
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Iraq (2003), and
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Syria/Iraq/Iran-related operations—
were carried out under AUMFs or executive authority, not a formal war declaration.
3. International Law
Under the UN Charter, force is only legal if:-
It is in self-defense, or
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Approved by the UN Security Council.
