In 1940, when the Second World War reached Norway with a German occupation, Raaen spoke out for "an active and honest cooperation with the authorities".[5] He then became unpopular with the resistance part of the trade unions.[6] In September 1940 he invited Nazi Birger Meidell to the national convention of the Norwegian People's Aid. For this he was removed as chairman, despite that Meidell did not show.[5] He was later viewed with suspicion by the anti-Nazi part of the labour movement. This was not changed even as he was arrested following the milk strike and incarcerated in Grini concentration camp.[7] He was imprisoned from 10 September 1941 to 19 February 1942.[8] After the Second World War he was not re-installed as leader of the Union of Employees in Commerce and Offices, officially for health reasons.[7]