Louis Fischer, a friend of Münzenberg's, he was afraid of possible reprisals if he returned to the USSR and was disturbed by the victimisation of figures such as Nikolai Bukharin. In late 1936, fellow KPD exile Walter Ulbricht, urged him to take up an offer from Dimitrov, then residing in Moscow, to return there and assume other missions on behalf of the Comintern.Dimitrov, Georgi. The Diary of Georgi Dimitrov, 1933-1949. Yale University Press, 2003. Münzenberg refused, as a result becoming persona non grata in the Communist movement. In early 1937 he was forced to yield control of the organisations he used for propaganda work to Bohumír Šmeral. The Communist Party press reported his expulsion from the party in April 1939 after the Comintern ICC had held hearings earlier in the year. Having been expelled from the German Communist Party (KPD), Münzenberg finally moved into open opposition to Stalin. A final article on the disgraced propagandist in the Comintern journal Die Internationale warned, "Unser fester Wille, die Einheit unter den Antifaschistischen herzustellen, unser Gefühl der Verantwortlichkeit vor dem deutschen Volk macht es uns daher zur Pflicht, vor Münzenberg zu warnen. Er ist ein Feind!" ("Our unshaking determination to unify anti-Fascists, our sense of duty before the German people, obliges us to warn them about Münzenberg. He is an enemy!") Münzenberg was an outspoken critic of the Molotov–Ribbentrop Pact, accusing Stalin of being a "traitor" to the working class and the cause of peace. Back in Paris, Münzenberg became a genuine leader of German émigré antifascism. The most important publication of his post-Communist Party period was Die Zukunft, a weekly whose contributors included German literary émigrés such as Alfred Döblin, Arnold Zweig, Thomas and Heinrich Mann, Franz Werfel, Ernst Toller and Lion Feuchtwanger, as well as international writers including Ignazio Silone, Aldous Huxley, François Mauriac, George Peabody Gooch, H. G. Wells, Julien Benda and Kingsley Martin, and global political and social figures such as Léon Jouhaux, Pietro Nenni, Francesco Saverio Nitti, Carlo Sforza, Clement Attlee, Georges Bidault, Jawaharlal Nehru, Norman Angell and Harold Macmillan. Die Zukunft continued to be published until the Battle of France in May 1940. It has been cited as the intellectual forerunner of Encounter and other Cold War publications. Münzenberg continued to work on behalf of antifascist causes throughout Western Europe, where he played a role in recruiting volunteers and acquiring Soviet arms for the International Brigades which