The Anglo-Irish War, 1919–21: Lessons from an Irregular Conflict

Abstract

The Anglo-Irish War of 1919–21, the first modern guerrilla war, offers many lessons relevant to today's counterinsurgency (COIN) operations. The Irish Republican Army (IRA), and de facto IRA commander-in-chief Michael Collins in particular, conducted a highly effective insurgent struggle against a British opponent lacking a coherent COIN strategy. For reasons discussed herein, however, the British government eventually was able to obtain an agreement that ended the war and protected its most vital strategic interests while nonetheless still permitting the creation of an Irish Free State. This study examines the character of Anglo-Irish War and draws a series of twenty-eight lessons from that conflict. The British dilemma: Whatever we do we are sure to be wrong. (General Sir Nevil Macready, Commander-in-Chief Ireland [GOC in C], 21 April, 1920). 1