A part of this power struggle was the opposition between power structures of the Soviet Union and the RSFSR. In an attempt to gain more power, on 12 June 1990, the Congress of People's Deputies of the RSFSR adopted a declaration of sovereignty. On 12 July 1990, Yeltsin resigned from the CPSU in a dramatic speech before party members at the 28th Congress of the Communist Party of the Soviet Union, some of whom responded by shouting "Shame!"