The French Popular Front could not have existed without the Radical Party. It was the French Communist Party which saw this most clearly and which took the initiative in opening the way for the Radicals to join the communist–socialist alliance, thereby extending what would otherwise have been a narrowly based working-class alliance into a major political force. Yet just as the Communists helped to create the alliance with the Radicals, so they helped to weaken it, and ultimately destroy it, in large part because of their reactions to events in Spain.

During the interwar period the Radical Party was pivotal: it was always solicited to form, or help form, the government during the governmental crises of the era. Even after the Popular Front electoral victory of May 1936, only a minority government could be constituted without the Radicals.

The Radicals were individualists while most of their partners were, or said they were, collectivists. The Popular Front itself was simply a variation on a perpetual theme of French political life: that the country voted left or right; that there was a party of movement and a party of order. The Radicals always considered themselves to be on the left of the political spectrum, but they were also a party of order par excellence. Radicals wanted social progress but only through order, discipline and legality. The explanation for this apparent paradox lay in the fact that the Radicals were such a mirror image of the contradictions which were France: both a revolutionary and a traditional country.