[1] Dahlén was elected to the second chamber of the Swedish parliament, from the northern constituency of Norrbotten, representing the Social Democratic Left Party.

[1][2] He was one of seven members of parliament belonging to the Social Democratic Left Party.

The group led by Karl Kilbom and Nils Flyg was expelled by the Executive Committee of the Communist International.

The expelled grouping reorganized themselves as a separate Communist Party of Sweden.

Dahlén did however, after a few months of vacillating, join the Kilbom-led Communist Party.