In accordance with Marxist theory, women who sold sex were viewed as being forced into prostitution in order to survive. The eradication of prostitution was thus vaunted as one of the major accomplishments of the Communist government and evidence of the primacy of Chinese Marxism. Prostitution did not exist as a serious object of concern in China for a period of nearly three decades. Recent studies have demonstrated, however, that the disappearance of prostitution under the Maoist government was far from complete. Pan Suiming, one of China's leading experts on prostitution, argues that "invisible" prostitution — in the form of women providing sexual services to cadres in exchange for certain privileges — became a distinctive feature of Maoist China, particularly towards the end of the Cultural Revolution.