Christensen’s and Snyder’s neorealist-based theory of buck-passing and chain-ganging uses offence-defence balance to predict state security policy choices under multipolarity. This approach is applicable to the US-led alliance system in the multipolar Indo-Asia-Pacific. Given regional Sino-US rivalry, hedging opportunities for US ‘hub-and-spoke’ allies will dissipate, increasing the likelihood of allies choosing to buck-pass or chain-gang in the face of conflict. With defence superior in the region, it is more likely that US allies will buck-pass rather than chain-gang. Beyond Indo-Asia-Pacific states, this has implications for global actors – such as the EU – seeking to raise their security profile in the region, as buck-passing behaviour gives greater time to adjust to potential conflict scenarios than chain-ganging.
Keywords: alliances, multipolarity, Indo-Asia-Pacific, balance of power, Sino-US rivalry