After the formation of the National Radical Union by Constantine Karamanlis, in 1955 he became a member of the party and one of the closest colleagues of Karamanlis, although, ideologically, he was a centrist-liberal and not a conservative.
Logo da formación da Unión Radical Nacional por Constantinos Karamanlís, en 1955 pasouse a este partido e converteuse nun dos colegas máis próximos de Karamanlis, aínda que aínda que, ideoloxicamente, el era un liberal de centro e non un conservador.