In this newsreel from December 1921, Éamon de Valera and Cathal Brugha are shown sitting in a car following their rejection of the Peace Treaty.
De Valera had famously not attended the negotiations himself in London but rather chose to stay in Ireland (as he would be better able to control the extremists at home). The Irish delegates who chose to attend the negotiations were Arthur Griffith, Robert Barton and Michael Collins supported by Robert Erskine Childers as Secretary General. The Treaty, which would replace the Republic by a dominion of the British Commonwealth, was signed on December 6th. De Valera was not happy with the signing of it as he had stipulated that regardless of the outcome the delegates should not be pressured into any agreements and should return to consult with the cabinet and him, their President.
After The Treaty was narrowly ratified, de Valera and a large majority of Sinn Féin T.D.s left Dáil Éireann and Arthur Griffith was elected President.