US-UK Mutual Defense Agreement: 60 years of unprecedented partnership

By Rebecca Ullrich

Thursday, December 06, 2018

This year, 2018, marks the 60th anniversary of the 1958 signing of the Mutual Defense Agreement between the United States and the United Kingdom.

Leadership attend MDA meeting at Sandia in 1958
SANDIA US-UK CONFAB — Among the leadership attending the 1958 meeting at Sandia, from left: Brig. Gen. A. D. Starbird, Chairman of the U. S. Delegation and Director Division of Military Application, AEC; R. W. Henderson, Vice President-Development, Sandia Corporation; Dr. Norris E. Bradbury, Director, Los Alamos Scientific Laboratory; Sir William Cook, Chairman, United Kingdom Delegation and Member of the Atomic Energy Authority; Dr. Edward Teller, Director, Livermore Laboratory of the University of California Radiation Laboratory; and Maj. Gen. Herbert B. Loper, Assistant to Secretary of Defense for Atomic Energy.  (Sandia archival photo)

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

Article I, General Provision:

While the United States and the United Kingdom are participating in an international arrangement for their mutual defense and security and making substantial and material contributions thereto, each Party will communicate to and exchange with the other Party information, and transfer materials and equipment to the other Party, in accordance with the provisions of this Agreement provided that the communicating or transferring Party determines that such cooperation will pro-mote and will not constitute an unreasonable risk to its defense and security.

Signed July 3, 1958

In force August 4, 1958

Currently extends to 2024

MDA 60th anniversary logo

For 60 years, the United States and the United Kingdom have shared ideas, information, materials and equipment within the enabling provisions of the Mutual Defense Agreement (MDA). Without limiting either nation’s independent actions, the MDA allowed for an unprecedented partnership in national security, including nuclear non-proliferation and counterterrorism, naval nuclear propulsion, and maintaining the basic integrity of each nation’s nuclear stockpile.

Under the auspices of the agreement, the two nations have established a system of liaisons and cooperative programs that define and support information sharing. That system was built in a series of meetings held after the MDA went into force in 1958. One of those meetings, held September 15-19 at Sandia, focused on sharing the weapons systems then in design or production.

1958 photo of woman holding bond campaign poster

OUT OF THIS WORLD CAMPAIGN — The U.S.S.R. launched the first artificial satellites — Sputnik I and II — in October and November 1957. The U.S. placed Explorer I in space two months later, so the cost and intensity of the Cold War were on everyone’s mind in 1958. Satellites were the focus of a May 1958 Bond Blitz during Sandia’s “Share in America” week. A major part of the campaign was signs and satellites in hallways around the Labs, emphasizing that government programs are not cheap and buying Savings Bonds is a way to loan money to Uncle Sam while gaining a guaranteed return.  (Sandia archival photo)

In 1958, the world was deep in the Cold War arms race and the competition, the stakes, and the politics were apparent to everyone involved in establishing and sharing under the umbrella of the MDA. For example, the 1958 theme for Sandia’s annual Savings Bond drive was satellites — Sputnik launched Oct. 4, 1957. The U.S. and U.K. had much to discuss about their respective nuclear weapons programs and how they might work together more closely in the future.

The 1958 meeting at Sandia was broken up into sessions — topical ones on theory and engineering and then sessions covering particular weapon systems. Each involved a great deal of discussion as scientists and engineers from the institutions involved in nuclear weapons design, development and use came together to understand each other’s work. They questioned each other’s decisions — not in a confrontational manner, but in an effort to understand differences in philosophy, approach, preferences and, ultimately, product. The sessions were recorded and transcripts produced. We know what they talked about in some detail.