Founding of Fine Gael
In 1933, anticipating another election that year, he founded the National Centre Party alongside James Dillon, and became the party's leader. The party was short-lived; MacDermot led the National Centre Party to merge with Cumann na nGaedheal and the Blueshirts to form Fine Gael that same year, and became a vice-president of the new party. It was reputedly MacDermot who devised the name of the party.
He was a persistent critic of Fianna Fáil and Éamon de Valera. He criticised the abolition of the oath of allegiance, the abolition of the Free State Seanad Éireann, the abolition of the Governor-General and the introduction of the Constitution of Ireland in 1937, arguing each time that these actions would make partition more secure, and arguing the need for rapprochement with the government of Northern Ireland and the wider unionist community. He continually stated that partition could only be addressed when Dublin-London relationships were normalised.
MacDermot had led the National Centre Party into Fine Gael on the pretense that members of the Irish Republican Army were breaking up meetings of Cumann na nGaedheal and other right-wing parties in support of the Republican Fianna Fáil, and that in order to survive the National Centre Party would have to band together with both Cumann na nGaedheal and Eoin O'Duffy's Blueshirts. However, with the accession of Fianna Fáil to power and tough anti-IRA measure put in place by de Valera, the marriage of convenience rapidly became undone. O'Duffy had become the initial leader of the party but by the summer of 1934 he had become an embarrassment to the other leaders and members of the party when he openly questioned the value of democracy after Fine Gael came second to Fianna Fáil in the 1934 local elections. MacDermot and other constitutionalists in the party rebuked O'Duffy's comments. By September 1934, O'Duffy had resigned as leader and left the party.
O'Duffy's departure did not increase MacDermot's comfort with the big tent of Fine Gael; he resigned from the party in 1935 when members of Fine Gael criticised de Valera for condemning the invasion of Ethiopia by fascist Italy at a meeting of the League of Nations.
