Though the party and journal folded in 1914 on the outbreak of war, Le Mercier d'Erm continued to play a leading role among young Breton nationalist activists between the wars.
Though the party and journal folded in 1914 on the outbreak of war, Le Mercier d'Erm help to found its replacement Breiz Atao in 1919. He continued to play a leading role among young Breton nationalist activists between the wars.