When in 1936, under the increasing threat of Japanese invasion, the Guomindang renewed their alliance with the Communists, Mao restored and vastly increased the political and military power of his Party. His claim to share in the government led to civil war; the regime of Jiang Jieshi was ousted from the Chinese mainland; and the new People's Republic of China was proclaimed (1949) with Mao as both Chairman of the Chinese Communist Party and President of the Republic. He followed the Soviet model of economic development and social change until 1958, then broke with the USSR and launched his Great Leap Forward, which encouraged the establishment of rural industry and the use of surplus rural labour to create a new infrastructure for agriculture. The failure of the Great Leap lost him most of his influence, but by 1966, with China's armed forces securely in the hands of his ally Lin Biao, he launched the Great Proletarian Cultural Revolution, and the Great Leap strategy was revived (with caution) when the left wing was victorious in the ensuing political struggles (1966–71). He died after a prolonged illness, which may have weakened his judgment. A strong reaction then set in against ‘cult of personality’ and the excessive collectivism and egalitarianism which had emerged during his time in power. A political, military, social, and economic essayist, he was also a significant minor poet.