“攘外必先安内”是“9·18”事变以后南京国民政府,蒋介石内政外交的基本政策.从“9·18”至西安事变,这一“基本国策”被贯彻执行达5年之久,对中国的政局发生了重大影响.研究这一政策,探讨南京政府确立这一政策的主客观原因,进而剖析、评述这一政策的内容、性质和作用,对于正确认识和估价国民党该段时期的历史地位与作用无疑是有意义的.本文拟对此作一初 “Internal Security Must Resist Foreign Aggression” is the Fundamental Policy of Nanjing National Government and Chiang Kai-shek’s Internal Affairs and Diplomacy since the “September 18th Incident.” From September 18 to the Xi’an Incident, the “basic national policy” was implemented for five years For a long time, has had a significant impact on China’s political situation.Researching this policy to explore the subjective and objective reasons for the Nanjing government to establish this policy, and then analyzing and commenting on the content, nature and role of this policy is of great significance to the correct understanding and valuation of the Kuomintang The historical status and role of the period undoubtedly makes sense