Iran’s relations with surrounding states exhibit a shift from unremitting radicalism to pervasive moderation, a transformation that is usually explained in terms of changes in the Islamic Republic’s domestic affairs. Yet the marked turn toward moderation may equally result from the dynamics of entrapment and pre-emptive realignment, which are inherent in alliance politics under conditions of anarchy. Attempts by Syria to strengthen ties to Iran set the stage for the 2006 Hizbullah–Israel war in Lebanon. Policy makers in Tehran recoiled from the fighting, opening the door to rapprochement with Ankara. Improved relations between Iran and Turkey both distanced the Islamic Republic from Iraq and prompted Iranian leaders to make unprecedented overtures to the Kurdistan Regional Government (KRG). Iran’s moves to conciliate Turkey and the KRG gained momentum as the Islamic State in Syria and the Levant seized territory across northern Syria and western Iraq. Nevertheless, ongoing Turkish initiatives in the Caucasus have created unpalatable strategic choices for the Islamic Republic, which put Tehran’s continued commitment to external moderation in jeopardy.