Hub-and-Spokes Alliance System

The hub-and-spokes model describes the architecture of U.S. security policy in East Asia after World War II, in which Washington signed separate bilateral defense treaties with regional partners rather than building a single multilateral alliance comparable to NATO. The United States serves as the "hub," while each ally—Japan, South Korea, the Philippines, Thailand, Australia (via ANZUS), and historically Taiwan—forms a "spoke" connected to Washington but not formally bound to one another.

The core treaties underpinning the system include the U.S.–Philippines Mutual Defense Treaty (1951), the ANZUS Treaty (1951), the U.S.–Japan Security Treaty (signed 1951, revised 1960), the U.S.–Republic of Korea Mutual Defense Treaty (1953), and the U.S.–Thailand alliance rooted in the Manila Pact (1954) and the Thanat–Rusk communiqué (1962). The U.S.–Taiwan Mutual Defense Treaty (1954) was terminated in 1980 following U.S. recognition of the PRC.

Scholars including Victor Cha have argued that the U.S. deliberately chose bilateralism—what Cha calls the "powerplay" rationale—to maximize control over potentially aggressive or unpredictable allies and prevent entrapment in regional conflicts. This contrasts with the multilateral approach taken in Europe through NATO (1949). Cultural heterogeneity, divergent threat perceptions, and the absence of a shared adversary equivalent to the Soviet threat in Europe also contributed to the bilateral pattern.

Contemporary debates focus on whether the system is evolving toward "networked" or "lattice-like" security cooperation. Initiatives such as the Quad (U.S., Japan, India, Australia), AUKUS (2021), and the trilateral Camp David summit between the U.S., Japan, and South Korea (August 2023) suggest growing minilateral linkages among the spokes themselves. Critics note the system's rigidity and its difficulty accommodating rising powers, while proponents emphasize its durability and the credibility of U.S. extended deterrence commitments in the Indo-Pacific.