# Rio Treaty (TIAR)
> The Inter-American Treaty of Reciprocal Assistance (commonly known as the Rio Treaty or TIAR) is a 1947 mutual defense agreement among many nations of the Americas. Its central principle is that an attack against one member is considered an attack against all, providing a legal framework for collective self-defense in the Western Hemisphere.
- URL: https://optimly.ai/brand/rio-treaty-tiar
- Slug: rio-treaty-tiar
- BAI Score: 82/100
- Archetype: Challenger
- Category: International Organization / Treaty
- Last Analyzed: May 7, 2026