ABCA Armies (formally, the American, British, Canadian, Australian and New Zealand Armies' Program) is a program aimed at optimizing interoperability and standardization of training and equipment between the armies of the United States of America, United Kingdom, Canada, Australia, and New Zealand, plus the United States Marine Corps and the Royal Marines. Established in 1947 as a means to capitalize on close cooperation between the United States, United Kingdom, and Canada during World War II, the program grew to include Australia (in 1963) and New Zealand (as an observer from 1965, with full membership in 2006).
ABCA Armies Wikipedia
The program started in 1947 as the "Plan to Effect Standardization" between the armies of the United States, United Kingdom, and Canada (the ABC Armies), with the three nations looking to capitalize on the close cooperation between the forces during World War II. In 1954, the Plan was replaced by the "Basic Standardization Concept".
Australia joined the organization in 1963, and the ABCA Program was established with the ratification of the "Basic Standardization Agreement 1964" on 1 October 1964. In 1965, Australia successfully sponsored the introduction of New Zealand to the agreement as an observer.
Originally, the role of ABCA was limited to issues of standardization for soldier equipment, training, and tactics. Following the September 11 attacks, a review by the Program's Heads of Delegations saw the Program modified to address the changing security environment and improve responsiveness, relevance, and focus on interoperability. The overhaul was completed by June 2004.
Also in 2004, the increasing involvement of the United States Marine Corps was formally recognized with a Memorandum of Understanding between the Corps and the United States Army, allowing both forces to be represented by a single position. Following this, the United Kingdom delegation successfully incorporated the Royal Marines. New Zealand became a full member of ABCA in late 2006.
Equivalent organizations for the nations' navies (AUSCANNZUKUS - Australia, Canada, New Zealand, United Kingdom and United States naval C4 organization), air forces (ASIC - Air and Space Interoperability Council), the military scientific communities (TTCP - The Technical Cooperation Program), and the Intelligence communities also exist.