Lê Duẩn, Ho Chi Minh's successor as party leader, preventing him from rising further in the hierarchy. In 1982, he was even removed from the Politburo. According to his friends, Linh resigned after an argument over the future of South Vietnam, in which he defended private capital. In the mid-1980s the Vietnamese economy experienced crisis, making a more liberal, market-based economy more of a sensible option to many politicians. This led to Linh's being re-instated in the Politburo in 1985 (and Permanent Secretariat 1986), under the direction of General Secretary Trường Chinh draft political report and even being made party general secretary the following year. Immediately, he started reforming Vietnam's economy. He was elected General Secretary in the immediate aftermath of the 6th National Congress. Renouncing the ideological decisions that he claimed had caused the problems, he allowed private enterprise and market prices and disbanded agricultural collectives. This change in policy was dubbed Doi Moi, a Vietnamese term meaning renovation. In the political sphere, Linh tried to improve relations with both the United States and China. In 1990, he secretly visited China, becoming the first Vietnamese leader to do so since the 1979 Sino-Vietnamese War. In 1989, he ordered the withdrawal of Vietnamese troops from Cambodia, where they had been sent to remove Pol Pot's Khmer Rouge regime. However, as far as domestic policy is concerned, Linh felt there was little need for change. "It is not objectively necessary to establish a political mechanism of pluralism and multiparty government," he stated, while always referring to Western-style democratic systems as "demagogic bourgeois democracies". He criticised the old communist policies, blaming them on corrupt leaders. Thus, Linh's policies were the constant target of criticism from the more conservative elements in the Communist Party. Linh stepped down as party leader in 1991 at the 7th National Congress, having announced his withdrawal a year before. His poor health was cited as the cause, as he had been hospitalised for what is suspected to have been a stroke in 1989, but political rivalries probably also played into his decision. He was succeeded by Đỗ Mười, a supporter of Linh's reforms. He was Advisor of the Party's Central Committee from 1991 to December 1997. Starting with a surprising speech at the 7th National Congress of the Communist Party of Vietnam and then series of letters to the country's newspapers, Linh eventually renounced the effects of his