Agreement between the Government of the United States of America and the Government of the United Kingdom of Great Britain and Northern Ireland for Cooperation on the Uses of Atomic Energy for Mutual Defence Purposes

E43855

bilateral treaty defence agreement nuclear cooperation agreement

The Mutual Defense Agreement (1958) is a landmark Cold War-era treaty that established extensive nuclear weapons and atomic energy cooperation between the United States and the United Kingdom for mutual defense.

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All labels observed (6)

Label	Occurrences
1958 US–UK Mutual Defence Agreement	2
Agreement between the Government of the United States of America and the Government of the United Kingdom of Great Britain and Northern Ireland for Cooperation on the Uses of Atomic Energy for Mutual Defence Purposes canonical	2
US–UK Mutual Defence Agreement	2
1948 US–UK Modus Vivendi on atomic energy cooperation	1
UK–US nuclear cooperation	1
US–UK nuclear weapons collaboration	1

How this entity was disambiguated

This entity first appeared as the object of triple T342776 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.

NED1 Entity disambiguation (via context triple) gpt-5-mini-2025-08-07

Target entity: Agreement between the Government of the United States of America and the Government of the United Kingdom of Great Britain and Northern Ireland for Cooperation on the Uses of Atomic Energy for Mutual Defence Purposes
Context triple: [Mutual Defense Agreement (1958), officialName, Agreement between the Government of the United States of America and the Government of the United Kingdom of Great Britain and Northern Ireland for Cooperation on the Uses of Atomic Energy for Mutual Defence Purposes]

A. UKUSA Agreement
The UKUSA Agreement is a post-World War II multilateral intelligence-sharing pact, originally between the US and UK, that underpins the global signals intelligence alliance now known as the Five Eyes.
B. 1960 Treaty of Mutual Cooperation and Security
The 1960 Treaty of Mutual Cooperation and Security is the foundational postwar defense pact between the United States and Japan that underpins their military alliance and the continued stationing of U.S. forces in Japan.
C. Joint Defence and Economic Co-operation Treaty of 1950
The Joint Defence and Economic Co-operation Treaty of 1950 is a foundational Arab League pact that established collective security and economic coordination among its member states in the early post–World War II era.
D. Atomic Energy Act of 1946
The Atomic Energy Act of 1946 was a landmark U.S. law that established civilian control over nuclear energy and created the Atomic Energy Commission to oversee the development and regulation of nuclear technology after World War II.
E. Wormley Agreement
The Wormley Agreement refers to the informal political deal that resolved the disputed 1876 U.S. presidential election by granting Rutherford B. Hayes the presidency in exchange for the withdrawal of federal troops from the South, effectively ending Reconstruction.
F. None of above. chosen
G. Unsure - the case is ambiguous/there is not enough information to decide.

NED2 Entity disambiguation (via description) gpt-5-mini-2025-08-07

Target entity: Agreement between the Government of the United States of America and the Government of the United Kingdom of Great Britain and Northern Ireland for Cooperation on the Uses of Atomic Energy for Mutual Defence Purposes
Target entity description: The Mutual Defense Agreement (1958) is a landmark Cold War-era treaty that established extensive nuclear weapons and atomic energy cooperation between the United States and the United Kingdom for mutual defense.

A. UKUSA Agreement
The UKUSA Agreement is a post-World War II multilateral intelligence-sharing pact, originally between the US and UK, that underpins the global signals intelligence alliance now known as the Five Eyes.
B. 1960 Treaty of Mutual Cooperation and Security
The 1960 Treaty of Mutual Cooperation and Security is the foundational postwar defense pact between the United States and Japan that underpins their military alliance and the continued stationing of U.S. forces in Japan.
C. Joint Defence and Economic Co-operation Treaty of 1950
The Joint Defence and Economic Co-operation Treaty of 1950 is a foundational Arab League pact that established collective security and economic coordination among its member states in the early post–World War II era.
D. Atomic Energy Act of 1946
The Atomic Energy Act of 1946 was a landmark U.S. law that established civilian control over nuclear energy and created the Atomic Energy Commission to oversee the development and regulation of nuclear technology after World War II.
E. Wormley Agreement
The Wormley Agreement refers to the informal political deal that resolved the disputed 1876 U.S. presidential election by granting Rutherford B. Hayes the presidency in exchange for the withdrawal of federal troops from the South, effectively ending Reconstruction.
F. None of above. chosen

Statements (48)

Predicate	Object
instanceOf	bilateral treaty ⓘ defence agreement ⓘ nuclear cooperation agreement ⓘ
alsoKnownAs	Mutual Defense Agreement (1958) ⓘ surface form: 1958 Mutual Defense Agreement Agreement between the Government of the United States of America and the Government of the United Kingdom of Great Britain and Northern Ireland for Cooperation on the Uses of Atomic Energy for Mutual Defence Purposes ⓘ surface form: 1958 US–UK Mutual Defence Agreement Mutual Defense Agreement (1958) ⓘ surface form: US–UK Mutual Defense Agreement
complements	North Atlantic Treaty ⓘ surface form: North Atlantic Treaty of 1949
context	Cold War ⓘ
countrySignatory	United Kingdom ⓘ surface form: United Kingdom of Great Britain and Northern Ireland United States of America ⓘ
dateSigned	1958-07-03 ⓘ
enables	cooperation on nuclear submarine propulsion ⓘ transfer of fissile material from the United States to the United Kingdom ⓘ transfer of nuclear warhead design information ⓘ
enteredIntoForce	1958-08-04 ⓘ
field	military nuclear technology ⓘ nuclear deterrence ⓘ
governs	transfer of special nuclear material for defence purposes between the United States and the United Kingdom ⓘ
hasBeenExtended	true ⓘ
historicalSignificance	cornerstone of US–UK nuclear weapons collaboration ⓘ first agreement allowing the United States to share detailed nuclear weapons design information with another state ⓘ
inForce	true ⓘ
initialDuration	10 years ⓘ
language	English ⓘ
legalBasis	Atomic Energy Act of 1954 ⓘ surface form: United States Atomic Energy Act of 1954
notableAmendment	1963 amendment expanding scope of cooperation ⓘ 1974 amendment following UK accession to the European Communities ⓘ 2004 renewal and amendment ⓘ 2014 renewal and amendment ⓘ
placeSigned	Washington, D.C. ⓘ
purpose	cooperation on the uses of atomic energy for mutual defence purposes ⓘ exchange of classified information on nuclear weapons design ⓘ exchange of special nuclear material for defence ⓘ nuclear weapons cooperation ⓘ
relatedTo	NATO ⓘ surface form: North Atlantic Treaty Organization Trident nuclear missile system ⓘ surface form: UK Trident nuclear weapons programme US–UK Polaris Sales Agreement ⓘ US–UK nuclear weapons cooperation ⓘ Anglo-American relations ⓘ surface form: US–UK special relationship
renewalInterval	10 years ⓘ
shortName	Mutual Defense Agreement (1958) ⓘ Agreement between the Government of the United States of America and the Government of the United Kingdom of Great Britain and Northern Ireland for Cooperation on the Uses of Atomic Energy for Mutual Defence Purposes self-linksurface differs ⓘ surface form: US–UK Mutual Defence Agreement
subjectMatter	atomic energy ⓘ exchange of nuclear materials ⓘ exchange of nuclear technology ⓘ exchange of nuclear weapons-related information ⓘ nuclear propulsion for naval vessels ⓘ nuclear weapons ⓘ

How these facts were elicited

Referenced by (9)

Full triples — surface form annotated when it differs from this entity's canonical label.

Mutual Defense Agreement (1958) → officialName → Agreement between the Government of the United States of America and the Government of the United Kingdom of Great Britain and Northern Ireland for Cooperation on the Uses of Atomic Energy for Mutual Defence Purposes ⓘ

US–UK MDA → fullName → Agreement between the Government of the United States of America and the Government of the United Kingdom of Great Britain and Northern Ireland for Cooperation on the Uses of Atomic Energy for Mutual Defence Purposes ⓘ

US–UK MDA → predecessor → Agreement between the Government of the United States of America and the Government of the United Kingdom of Great Britain and Northern Ireland for Cooperation on the Uses of Atomic Energy for Mutual Defence Purposes ⓘ

this entity surface form: 1948 US–UK Modus Vivendi on atomic energy cooperation

Agreement between the Government of the United States of America and the Government of the United Kingdom of Great Britain and Northern Ireland for Cooperation on the Uses of Atomic Energy for Mutual Defence Purposes → shortName → Agreement between the Government of the United States of America and the Government of the United Kingdom of Great Britain and Northern Ireland for Cooperation on the Uses of Atomic Energy for Mutual Defence Purposes self-linksurface differs ⓘ

this entity surface form: US–UK Mutual Defence Agreement

Agreement between the Government of the United States of America and the Government of the United Kingdom of Great Britain and Northern Ireland for Cooperation on the Uses of Atomic Energy for Mutual Defence Purposes → alsoKnownAs → Agreement between the Government of the United States of America and the Government of the United Kingdom of Great Britain and Northern Ireland for Cooperation on the Uses of Atomic Energy for Mutual Defence Purposes ⓘ

this entity surface form: 1958 US–UK Mutual Defence Agreement

Nuclear weapons policy of the United Kingdom → cooperationFramework → Agreement between the Government of the United States of America and the Government of the United Kingdom of Great Britain and Northern Ireland for Cooperation on the Uses of Atomic Energy for Mutual Defence Purposes ⓘ

this entity surface form: 1958 US–UK Mutual Defence Agreement

Quebec Agreement → established → Agreement between the Government of the United States of America and the Government of the United Kingdom of Great Britain and Northern Ireland for Cooperation on the Uses of Atomic Energy for Mutual Defence Purposes ⓘ

this entity surface form: US–UK nuclear weapons collaboration

Quebec Agreement → influenced → Agreement between the Government of the United States of America and the Government of the United Kingdom of Great Britain and Northern Ireland for Cooperation on the Uses of Atomic Energy for Mutual Defence Purposes ⓘ

this entity surface form: US–UK Mutual Defence Agreement

Dreadnought programme → technologySharingContext → Agreement between the Government of the United States of America and the Government of the United Kingdom of Great Britain and Northern Ireland for Cooperation on the Uses of Atomic Energy for Mutual Defence Purposes ⓘ

this entity surface form: UK–US nuclear cooperation

All labels observed (6)

How this entity was disambiguated Show

Statements (48)

How these facts were elicited Show

Referenced by (9)

How this entity was disambiguated

How these facts were elicited