In August 1963, the United States and the Soviet Union signed the Nuclear Test Ban Treaty. But that was only half the story: To be enacted, the Test Ban had to be ratified by the U.S. Senate. President Kennedy was pessimistic. He confided in aides that getting this “controversial treaty” through the Senate was “almost in the nature of a miracle.” And yet, two months later, the Test Ban was ratified by an overwhelming majority.

So, what happened? This thesis gives the answers. It provides the first analytical narrative of the campaign for ratification Kennedy and his allies waged in the summer of 1963. It not only examines White House strategy and Senate proceedings, but also grassroots activism, thereby drawing attention to domestic imperatives in the enactment of the treaty.

Ultimately, this thesis argues, Kennedy’s campaign achieved more than its legislative objective. It made peaceful coexistence with the Soviet Union a popular position and engendered the Summer of Peace; a political atmosphere where many, be they hawks or doves, thought the Cold War was nearing its end. Kennedy, in turn, used the momentum of the Summer of Peace to engineer a rapprochement with the Soviet Union. The endgame: to end the Cold War. But Kennedy died in November 1963, just as he was making headway.

By identifying a distinct moment in the Cold War—which lasted another three decades—when peace beckoned, this thesis emphasises the importance of contingency in history.