This thesis examines the influences on and evolution of the Irish Republican Army’s guerrilla war strategy between 1917 and 1921. Utilizing newspapers, government documents, and memoirs of participants, this study highlights the role of propaganda and political concerns in waging an insurgency. It argues that while tactical innovation took place in the field, IRA General Headquarters imposed policy and directed the conflict with a concern for the political results of military action. While implementing strategies necessary to effective conduct of the war, this Headquarters staff was unable to reconcile a disjointed and overburdened command structure, leading its disintegration after the conflict.