Abstract: During the time of the Johnson administration, U.S. military and the government had heated and long-lasting debates on the deployment of the Nike-X ABM system against the backdrop of national defense strategy adjustment. The Johnson administration finally decided to deploy a limited ABM system in some selected regions for such reasons: internal political struggle, intention to force the Soviets to join in the arms control negotiation, and defense against the third party’s missile strike. This was the first official ABM deployment decision in American history, which deeply influenced America’s ABM deployment policy afterwards.