Along with Arthur Griffith, Michael Collins and Eoin O'Duffy, O'Higgins is an important figure in Irish nationalist historiography, representing a more "conservative revolutionary" position when contrasted with republicanism. After having a role in the Irish War of Independence, he went on to defend the nascent Irish Free State, as part of the pro-Treaty side in the Irish Civil War. During this time he signed the execution orders of seventy-seven political prisoners. He was later assassinated in retaliation by an IRA unit in Booterstown, County Dublin.