Operation Crossroads (1946, 1947)


A revealing Top Secret Restricted Data* formerly classified memo from General Curtis Lemay and the Joint Chiefs of Staff Evaluation Board to General Carl Spaatz on Operation Crossroads, the first nuclear test in the Marshall Islands.

Of note are the memo’s conclusions that clearly lay out the devastating effects of nuclear weapons:

(1) “Atomic bombs in numbers conceded to be available in the foreseeable future can nullify any nations military effort and demolish its social and economic structures.”

(2) “In conjunction with other mass destruction weapons it is possible to depopulate vast areas of the earth’s surface, leaving only vestigial remains of man’s material works.”

Also significant is the emphasis on the “redefinition” of an “aggressive act” to “prevent a nation-wide ‘Pearl Harbor.’”

Read the memo.


* Restricted Date is defined as “all data concerning the following, but not including data declassified or removed from the RD category pursuant to section 142 of the Atomic Energy Act” including:

design, manufacture, or utilization of atomic weapons
production of special nuclear material; or use of special nuclear material in the production of energy
mass or dimensions of fissile materials, pits, or nuclear assembly systems
efficiency of nuclear materials
boosting systems
initiator design
test information revealing RD
naval nuclear propulsion information
radiological warfare

RD is Born Classified.

See the McMahon Act (AEC, 1954); Arvin S. Quist. Chapter 3. “Classification of Information”  and “Principles for Classification of Information.