On 18 June 1950, in Cairo, the member states of the Arab League sign the Treaty of Joint Defence and Economic Co-operation — the League’s collective-security instrument after the first Arab–Israeli war.

The treaty creates the Joint Defence Council and the Economic Council (renamed Economic and Social Council in 1980), both reporting to the Council of the Arab League.

The text provides mutual assistance in case of aggression and economic coordination among members. Authentic language: Arabic.

Though often invoked rhetorically, military application was uneven; the economic institutions nonetheless fed Arab industrial-integration projects.

For post-1948 Arab diplomacy, 18 June 1950 marks the formalisation of collective security within the League.

The Avalon text remains the standard English diplomatic source.

The Joint Defence Treaty of 18 June 1950 remains the Arab League’s collective-security pact.

Image: Cairo / Arab League; Wikimedia Commons. Cropped to 16:9.

Source consulted: Joint Defence and Economic Co-operation Treaty. Treaty text: Treaty of Joint Defence and Economic Co-operation (Avalon).