He subsequently became less of a central figure following the German occupation of Belgium during World War II due to his lukewarm attitude towards working with Nazi Germany.
[1] While working as a teacher and academic, Streel joined l'Action Catholique de la Jeunesse Belge in 1930 and whilst in this organisation he became close to Léon Degrelle and Jean Denis.
[1] As such he was an early member of the Rexist movement and rose to prominence with his 1932 work, Les Jeunes Gens et la Politique, which underlined his distaste for the modern world.
[1] He argued against democracy and in favour of an organic society, rejecting government by political parties and underlining what he perceived as the importance of group membership on the basis of family, regional, cultural and nationalistic identities.
[1] He became editor of Le Pays Réel in August 1940 when it re-appeared, and with Degrelle enlisting in the German forces, he became an important advisor to the new Rexist leader Victor Matthys.
[1] Brought before the Brussels War Tribunal, he was defended by Paul-Henri Spaak and other leading figures and initially his sentence was commuted to life imprisonment with hard labour.