1949(民國38)年中國大陸陷共以後,美國對遷台的中華民國政府,態度十分冷淡;翌年夏韓戰爆發後,美國基於圍堵戰略之考量,態度始趨於積極。1951年1月底,美國表示願向台灣提供若干軍事援助,但重要條件之一,就是美國軍援顧問團駐台人員構成美國駐華大使館之一部份,享有治外法權;我政府予以同意。此一背景,應是1957年5月台北「劉自然事件」發生的重要根源。 1957年3月我國公民劉自然遭美軍援顧問團上士雷諾(Robert G. Reynolds)槍殺斃命,經我外交部交涉後,美軍終於組成軍事法庭,於同年5月20日開庭審理,經三日之審訊,兇嫌雷諾被宣判無罪。24日上午,劉氏遺孀在美大使館門前舉牌抗議,得民眾之同情,終釀成該日下午群眾搗毀美國大使館、撕毀美國國旗事件。美國政府隨即表達了嚴重抗議,我政府隨後以道歉、緝捕滋事份子及賠償美使館損失加以回應,總算沒有使當時中華民國政府十分依重的台美關係,裂痕為之加大。美軍人員之「治外法權」問題,遲至1965年8月中美簽訂〈美軍在華地位協定〉後,始獲得一合理之解決;惟美國軍事援華顧問團人員,因已另有規定,並不受此協定之拘束。至於因劉案而擴大的我中央政府行政革新運動,卻也因此而意外獲得若干成效。
In 1949, the United States (US) maintained a very distant attitude towards the Republic of China (ROC). This turned to strong positive support after the Korean War broke out in the summer of 1950, as the US hoped to include Taiwan in its strategy of containment of Communism. On January 30, 1951, the US expressed a willingness to provide Taiwan with a form of military aid; however, one of the key conditions was that all members of the US Military Assistance Advisory Group (MAAG) in Taiwan should be granted extraterritorial jurisdiction, to which the ROC government agreed without hesitation. This prevailing condition became an essential factor in the Liu Tzu-jan Incident that broke out in Taipei in May of 1957. In March 1957, Sgt. Robert G. Reynolds of the MAAG shot and killed an ROC national, Liu Tzu-jan. Following a series of diplomatic exchanges, the US convened a military court tried the case on May 20th in Taipei. After a three-day trial, Sgt. Reynolds was acquitted. In light of the verdict, Liu's widow protested in front of the US Embassy on the morning of May 24th. The protest won public sympathy and by the afternoon, it escalated into a mob, which broke into and looted the US Embassy, and burnt the US flag. The US Government immediately expressed a serious protest against the mob action. The ROC Government apologized for the incident and arrested a group of agitators involved; furthermore, it compensated the US Embassy for its losses. In this way it prevented a serious rift in US-Taiwan Relations, upon which the ROC Government was heavily reliant. The ”extraterritorial jurisdiction” problem finally received a reasonable resolution under the ”Status of Forces Agreement with the Republic of China” concluded in August 1965, although this Agreement did not extend to the personnel of MAAG. The incident had a further unintended effect of expanding the movement for administrative reforms within the ROC Government.