In 1971, the politically-radical phase of the Cultural Revolution (1966–1976) concluded with the failure of Project 571 (the coup d'état to depose Mao) and the death of the conspirator Marshal Lin Biao (Mao's executive officer), who had colluded with the Gang of Four — Jiang Qing (Mao's last wife), Zhang Chunqiao, Yao Wenyuan, and Wang Hongwen — to assume command of the People's Republic of China. As reactionary political radicals, the Gang of Four argued for regression to Stalinist ideological orthodoxy at the expense of internal economic development, but soon were suppressed by the PRC's secret intelligence service.[61]