In October 1950 the Chinese leader Mao Zedong embarked on a two-front war. He sent troops to Korea and invaded Tibet at a time when the People's Republic of China was burdened with many domestic problems. The logic behind Mao's risky policy has baffled historians ever since. By drawing on newly available Chinese and Western documents and memoirs, this article explains what happened in October 1950 and why Mao acted as he did. The release of key documents such as telegrams between Mao and his subordinates enables scholars to understand Chinese policymaking vis-à-vis Tibet much more fully than in the past. The article shows that Mao skillfully used the conflicts for his own purposes and consolidated his hold over the Chinese Communist Party.