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 Britain marked the occasion with a dinner in his honour and the toast was 'Anglo-Irish Friendship'. A key message in de Valera's campaign was that Ireland could not join the recently established North Atlantic Treaty Organization as long as Northern Ireland was in British hands; although the coalition government favored alliance with NATO, de Valera's approach won more widespread support and prevented the state from signing onto the treaty. Returning to Ireland, during the Mother and Child Scheme crisis that racked the First Inter-Party Government, de Valera kept a dignified silence as Leader of the Opposition, preferring to stay aloof