In 1913, she became the president of the Union of Domestic Workers of Germany, requiring her to move back to her home city of Berlin. During World War I Kähler supported left wing SPD politicians, that included Clara Zetkin and Rosa Luxemburg in rejecting the party's policy of "Burgfrieden" (a truce with the government, promising to refrain from any strikes during the war) and attended an international socialist women's anti-war conference in Berlin organised by Zetkin in 1915. After the War Germany and Berlin witnessed a period of politically driven civil conflict known as the German Revolution during which the imperial government was replaced by the Weimar Republic. As a notable feminist and union official Luise Kähler was instrumental in leading her Union through the turmoil caused by the civil unrest. The new republic in Germany needed to reform its archaic domestic servant laws particularly since thousands of domestic workers were giving up their employment as the economy of the Weimar Republic went into free fall. Many smaller unions survived only by merging into larger conglomerations.