In The Adversary's Veto, Joshua Byun investigates why great powers so often struggle to shape how their smaller allies prepare for war. When a great power seeks to enlist its allies in checking a formidable adversary, some allies readily adapt their military capabilities to the great power's grand strategy while others do not. Conventional wisdom holds that this pattern stems from the great power's excessive generosity. Byun argues otherwise. Distinguishing between "outsourcing" grand strategies-which devolve military assets and responsibilities to smaller allies-and "insourcing" strategies-which centralize discretion over military decisions in the hands of the great power-he shows that allies' responses to either strategy are shaped less by what the great power offers or withholds than by the risks that allies perceive from a hostile great power outside the alliance. Byun examines US and Soviet alliance relations during the Cold War alongside contemporary cases in East Asia. Allies highly vulnerable to military predation resist outsourcing strategies, fearing arms races or preventive attack, but accommodate insourcing. Relatively invulnerable allies do the opposite-embracing outsourcing while defying insourcing in pursuit of independent capabilities. From West Germany and France in the Cold War to Japan and South Korea today, allied behavior, Byun argues, tracks less the great power's generosity and more the adversary's looming veto. In an era of intensifying great power competition, The Adversary's Veto compels scholars and policymakers to reckon with a hard truth: there is little a great power can do to override how an ally interprets the dangers posed by a nearby adversary.
