The currently emerging debate on the desirability of the U.S. undertaking to deploy an anti-ballistic missile defense system (A.B.M.) threatens to become the next national defense issue to have an impact on national elections. In the past we have all become familiar with real or alleged “bomber gaps,” “missile gaps,” and “conventional gaps.” The basis for all these “gaps” was a deep fear that potential enemies would subject ns to nuclear blackmail, or that our own failure to develop other kinds of military forces would require us to respond to any emergency with an all-out nuclear attack.

In an earlier essay, I pointed out how our obsession with nuclear war had encouraged us to discount the significance of conventional war. I want now to turn to an examination of how specific groups in the U.S. have changed their positions in recent years on the subject of defensive weapons. In doing so I have borrowed the term used in 1960 by Henry Kissinger to describe the shifting arguments of the Air Force and Navy.