1983年3月23日雷根總統提出著名之「戰略防禦計畫」演說，呼籲美國科學界應立即將自身偉大才能轉移到確保人類與世界和平上，讓美國有能力使核武變成「無效」及「過時」。雷根於演說中所勾勒之飛彈防禦系統遠景，與歷屆美國政府相比，可謂「空前絕後」，引發美國國內第二次針對飛彈防禦展開大辯論。 雷根政府之「戰略防禦計畫」決策，最關鍵因素為雷根本人對於美國應建立飛彈防禦能力之信念，特別是對於「相互保證毀滅」核武嚇阻戰略之不認同。雷根在就任前便主張重建美國軍力與蘇聯對抗，「戰略防禦計畫」在雷根上任前兩年並未提出，主要是因為當時雷根政府優先目的在重建傳統軍力與戰略核武能力，然雷根政府提出之MX飛彈計畫遭國會反對，引發雷根提出「戰略防禦計畫」之決心。 雷根政府在「戰略防禦計畫」決策，係由在雷根授意下由國安會與白宮幕僚以秘密方式進行，目的在利用美國科技與經濟優勢壓迫蘇聯，並提高美國與蘇聯談判地位，國務卿舒茲與國防部長溫柏格等重要官員事前並不清楚決策過程，然事後均忠心支持雷根之決定。 雷根堅持「戰略防禦計畫」非美蘇談判交易籌碼，加上他堅持落實「裁減核武」之美蘇軍備控制談判比「限制核武」更有意義，以及美國對美蘇冷戰所設定之目標應為「勝利」而非僅「圍堵」，充分體現其領導風格與外交思維之獨特，此為後世稱之為「雷根主義」，並將冷戰結束、蘇聯瓦解歸功於雷根之主因。 On March 23, 1983, President Ronald Reagan made his famous speech on the “Strategic Defense Initiative.” In the speech, President Reagan called for the U.S. scientific community to turn their great talents to give the U.S. means of rendering these nuclear weapons impotent and obsolete. The missile defense vision described by President Reagan was unprecedented, and therefore induced a great debate within the U.S. on this issue. The most important factors of President Reagan’s decision to push forward the “Strategic Defense Initiative” was President Reagan’s own conviction on the need for the U.S. to possess missile defense capability, and President Reagan did not agree with the nuclear deterrence doctrine of “Mutual Assured Destruction.” President Reagan believed that the U.S. should rebuild its overall military strength to compete with the Soviet Union. However, during the first two years of Reagan Administration, the focus of the rebuilding military task was on conventional forces and strategic nuclear arms. Until the MX missile deployment plan was blocked by the U.S. Congress, Reagan Administration began to push forward the “Strategic Defense Initiative.” The preparation of President Reagan’s “Strategic Defense Initiative” was conducted secretly by the NSC and specific White House officials with the authorization from President Reagan. And the main purpose of this policy was to exploit U.S. technological and economical advantages to pressure Soviet Union as well as to improve U.S. position on arms control negotiations with Soviet Union. Although key national security officials like Schultz and Weinberger did not know much about President Reagan’s decision to propose the “Strategic Defense Initiative” On March 23, 1983, both of them faithfully obeyed President Reagan’s decision afterward. President Reagan insisted that the “Strategic Defense Initiative” is not a bargain chip of the U.S.-Soviet negotiations, a “arms reduction” is more meaningful than “arms limitation,” and he believed that the U.S. “Cold War” strategy should be “victory” not “containment” demonstrate the uniqueness of his leadership and diplomatic thinking. That is the main reason why it was called by many as the “Reagan Doctrine”, and many people give the credit of “ending the Cold War” and “the demise of Soviet Union” to him.