一九五o 年韓戰爆發，打亂了杜魯門原先準備放棄台灣承認中共的計畫，美國只好暫時重新支持國民政府。但在現實政治需要下，美國自杜魯門以至甘迺迪、詹森政府始終從沒放棄與中共修好，建立交往的企圖。因此，在冷戰要求下，美國固然承認台北是代表中國惟一合法政府；然而在現實需要中，又必需與北京發展關係的分裂操作下，出現美國對華「兩個中國」政策的行徑路線。影響所及，美國在面對每年聯合國大會「中國代表權問題」表決時，美國政府在兩個中國政策指導下，試圖將兩岸並存於聯合國「雙重代表」設計的這一平行配套路線。直到一九七一年十月，我正式退出聯合國，一直是美國作為解決對華關係的主流思維模。本文之論述，將探討五O~六O 年代，美國對華之「兩個中國」政策與「雙重代表權」的平行互動；相關資料採證將根據中華民國國史館之聯合國【兩蔣總統檔案】與FRUS(美國外交關係)解秘檔案，由史料的對比，證諸美國採行「兩個中國」對華政策與在聯合國處理「中國代表權」問題之平行發展：由杜魯門的「袖手」政策以至「台灣地位未定論」配合「緩議案」；甘迺迪再以「外蒙案」，改以「重要案」，動搖國府在聯合國「一中一席」立場；至詹森時，不論是「中法建交」及「研究委員會案」，已有輕舟已過萬重山之態，這些事件不但是了解當時美台關係的重要內容，也透露了美國在六o 年代前對華政策的真相。

Till US-PRC Shanghai Communique of 1972 was signed, US governments had
persistently fulfilled a two-China policy toward her diplomatically recognized ally- ROC.That was best proved in forming her strategies to resolve the UN Chinese Representation Question (CHIREP), arguing which side–Taipei or Beijing was the sole legal member to represent the whole China.The paper will reveal a parallel progress between a US two-China line and her UN “dual representation” one before 1970. The process started with Truman’s attempted Hands Off policy to abandon Taiwan and suddenly shifted to an purposed “undecided status” of Taiwan when Korean War broke out in 1950. In collaboration, it was to design a moratorium in UN to act as a wait-and-see tactics. In the coming 1960, Kennedy first bended Chiang Kai-Shek’s“rather be a jade broken than a tile intact” will to retreat to support Outer Mongolia’s admission to UN and humbly accept Important Question proposal ,promising Albanian Resolution to remove Taipei seat from UN be in the UN table every year. In the Johnson
administration, either China-France diplomatic recognition or Study Committee proposal all proved two China policy and dual recognition are like two sides of a coin in the minds of US policymaker during 1950s and ‘60s.This paper greatly relies on lately declassified official documents from ROC Academia Historica and Foreign Relations of US. Those first-hand data showed two China policy was undergone until Taipei failed to keep her UN seat with dual representation in the 26th UN Assembly, 1971 . In 1972, US acknowledged in Shanghai Communiqe one China principle,
which was interrupted in 1950.