 Complete the following phrase:  In December 1920 Dahlem took part in the unification party conference at which the left wing of the USPD merged with the German Communist Party to form what was briefly known as the . Here, together with Philipp Fries and Henriette Ackermann, he was elected to the local party leadership of the Middle Rhine region. He also briefly represented Middle Rhine nationally on the party central committee. In 1921 he surrendered his editorship of the Sozialistische Republik, but during 192122 he briefly edited the Berlin-based Internationalen Presse-Korrespondenz. When the French army occupied the 