Events unfolded at a relentless pace: On September 18, 1931, the Mukden Incident occurred, and the following year the Japanese invaded Manchuria. Outright war between China and Japan loomed. The Nationalist government was torn between "repelling the extercal threat" (fighting the Japanese) and "achieving internal security" (fighting the communists).
無奈時局變化得太快：民國二十年，九一八事變，第二年東北變色，中日戰火一觸即發，「安內」和「攘外」何者優先，成了政治難題。