That nearly split the UAW. After skirmishes at the UAW headquarters and some local unions, the expelled Executive Board members, with the support of the CIO, regained control in 1939 and expelled Martin. He left with about 20,000 members to form his own union, which affiliated with the American Federation of Labor (AFL). Lovestone left with him. The CP was in a particularly strong position at that point: it was the leading player in the Left-Center coalition that had defeated Martin and would have been able to elect George Addes, a close ally of the Party, as President of the UAW if it had pressed the point. But that would have required that the Party defy Sidney Hillman, head of the Amalgamated Clothing Workers of America and the most powerful force within the CIO after Lewis, and Philip Murray, Lewis' protégé and head of the Steel Workers Organizing Committee, who came to the convention to demand the selection of R.J. Thomas, an apolitical Board member who had, until recently, supported Martin, as its candidate to end the factional fighting within the UAW. According to some reports, when Hillman and Murray could not bring Mortimer and his supporters around, Earl Browder, Chairman of the Communist Party of the USA (CPUSA), came to Cleveland to demand that they support Thomas. Eager not to appear as sectarians and thus endanger their role within the CIO at large, the CP leadership had the Communists within the UAW support Thomas and also permit the elimination of the Vice-President positions that they had held. At the same time, the CP began dissolving its factions within the UAW and dropping its shop papers as it aligned itself even more closely with the New Deal. In the name of labor unity, the CP undertook a tactical retreat. The CP's conciliatory stance did not, however, protect it from its other factional rivals within the UAW. The working alliance between the CP and the Socialists in the UAW had broken down in 1938 over differences over the CP's support for "collective security," an alliance of the Soviet Union with the non-fascist nations of the West against Hitler. The Socialist Party, at that time even further left than the CP on many issues, organized a separate caucus within the Executive Board that, from that point forward, opposed the CP and its alliance partners. The CP made it easier for its opponents by making a number of sudden and shocking changes in policy. After the Hitler-Stalin pact, the CP campaigned vigorously against any U.S. involvement in the war against fascism; a journalist with the CP's Weekly Worker newspaper coined the slogan "The Yanks Ain't Coming" to sum up the Party's position.