Sinn Féin for nine years. (It merged with two other organisations to form Fine Gael in 1933.) Anti-Treaty Sinn Féin members continued to boycott the Dáil. At a special "Ard Fheis" in March 1926, de Valera proposed that elected members be allowed to take their seats in the Dáil if and when the controversial Oath of Allegiance was removed. When his motion was defeated, de Valera resigned from Sinn Féin; on 16 May 1926, he founded his own party, Fianna Fáil, which was dedicated to republicanising the Free State from within its political structures. He took most Sinn Féin TDs with him.
Éamon de Valera and Collins would later become opponents during the Irish Civil War. In January 1921, in his first appearance in the Dáil, after his return to a country gripped by the War of Independence, de Valera introduced a motion calling on the IRA to desist from ambushes and other tactics that were allowing the British to successfully portray it as a terrorist group, and to take on the British forces with conventional military methods. This they strongly opposed, and de Valera relented, issuing a statement expressing support for the IRA, and claimed it was fully under the control of the Dáil.