The suppression of specific intellectuals in the Anti-Rightist campaign turned into anti-intellectualism in general in the Great Leap Forward (GLF). In contrast to the Hundred Flowers period, the GLF emphasized political reliability rather than professional skill. The Anti-Rightist Campaign and GLF had silenced and demoralized a larger number of intellectuals than the Hu Feng campaign of 1955. In May 1961, P'eng Chen instructed his closest deputies in the Peking Party Committee to evaluate the GLF. At the Tenth Plenum, held in September 1962, Mao Tse-tung announced a shift from the relative relaxation of the early 1960s to increased control over intellectual activity. He called for ideological class struggle, which was an implicit summons for an attack on his critics. The arguments, rhetoric, and symbols used in the 1963-64 debates with the senior intellectuals provided the ideological underpinnings for the Cultural Revolution. The major flank of the radical attack on the cultural establishment was the effort to reform Peking Opera.