Why do states join ad hoc military coalitions? What motivated South Korea to contribute significantly to the Iraq War 'coalition of the willing', while such steadfast allies as Turkey and Germany resisted US pressure to become burden-sharing partners? Drawing on his extensive examination of South Korean, German, and Turkish politics in the approach to and during the Iraq War, Daniel Baltrusaitis offers an in-depth analysis of how domestic political dynamics critically influence a state's level of material and diplomatic support to 'coalitions of choice'.