Berger was very active in the biggest party controversy of the pre-war years, the fight between the SP's centrist "regular" bloc against the syndicalist left wing over the issue of "sabotage." The bitter battle erupted in full force at the 1912 National Convention of the Socialist Party, to which Berger was again a delegate. At issue was language to be inserted into the party constitution which called for the expulsion of "any member of the party who opposes political action or advocates crime, sabotage, or other methods of violence as a weapon of the working class to aid in its emancipation." The debate was vitriolic, with Berger, somewhat unsurprisingly, stating the matter in its most bellicose form: