Following Hu Yaobang's resignation as general secretary of the Chinese Communist Party on 16 January 1987, the political and economic reforms sponsored by Deng Xiaoping since 1978 came under intense criticism. Warning against “bourgeois liberalization” and renewed “spiritual pollution” from the west, Party conservatives reacted to student demonstrations in December 1986 by reversing the “Double Hundred” policy of literary and scientific freedom and by engineering the purge of the ardent westernizers Fang Lizhi, Liu Binyan and Wang Ruowang. Deng Liqun's “Leading Group to Oppose Bourgeois Liberalism,” Chen Yun's Central Discipline Inspection Commission (CDIC), and the outspoken Peng Zhen emerged as the main ideological watchdogs favouring restrictions on individual expression. But even the pro-reformer Zhao Ziyang condemned western ideas as “pernicious,” just as his chief secretary Bao Tong, warned intellectuals against “writ[ing] only about (the merits) of developed capitalist countries.”