Soviet leader Brezhnev hesitated to intervene militarily in Czechoslovakia. Dubček's Action Program proposed a "new model of socialism"—"democratic" and "national." Significantly, however, Dubček did not challenge Czechoslovak commitment to the Warsaw Pact. In the early spring of 1968, the Soviet leadership adopted a wait-and-see attitude. By midsummer, however, two camps had formed: advocates and opponents of military intervention. The pro-interventionist coalition viewed the situation in Czechoslovakia as "counterrevolutionary" and favoured the defeat of Dubček and his supporters. This coalition was headed by the Ukrainian party leader Petro Shelest and included communist bureaucrats from Belarus and from the non-Russian national republics of the western part of the Soviet Union (the Baltic republics). The coalition members feared the awakening of nationalism within their respective republics and the influence of the Ukrainian minority in Czechoslovakia on Ukrainians in the Soviet Union. Bureaucrats responsible for political stability in Soviet cities and for the ideological supervision of the intellectual community also favoured a military solution. Within the Warsaw Pact, only the German Democratic Republic (East Germany) and Poland were strongly interventionist. Walter Ulbricht and Władysław Gomułka—party leaders of East Germany and Poland, respectively—viewed liberalism as threatening to their own positions.