Platformization Without High Commitment: The Institutional Resilience and Functional Limits of the Quad

ABSTRACT

Since its revival in 2017, the U.S.–Japan–India–Australia Quadrilateral Security Dialogue (Quad) has continued to operate across multiple changes of government in its member states despite the absence of legally binding security commitments, and has extended its cooperation into a range of functional domains. Yet it has never developed into a defense pact carrying mutual‐defense obligations, nor into a more tightly binding security‐cooperation mechanism. This article understands the Quad as a low‐commitment minilateral security arrangement and proposes “platformization without high commitment” as a middle‐range analytical framework. The framework explains why a single institutional design can both sustain cooperation under conditions of pronounced divergence in members' preferences and, at the same time, make it difficult for the mechanism to move beyond its existing boundaries into domains that would require members to make explicit security commitments. The article argues that the institutional resilience of platformization derives from the combined operation of three mechanisms—political anchoring, network support, and functional endorsement—rather than from shared threat perception or U.S. leadership alone. At the same time, differences among members in their security concerns and risk assessments, the functional division of labor among Indo‐Pacific security mechanisms, and the Quad's deliberate restraint in avoiding the appearance of an exclusive military bloc together limit its functional expansion. Through process tracing of the Quad's evolution from 2017 to 2026, the article shows that the low‐commitment design has allowed the Quad to convert member differences into manageable institutional conditions and thereby sustain cooperation; but the same institutional features also delimit its role in collective defense, collective enforcement, and high‐risk crisis response.