Most Americans agree that our protracted involvement in the defense of South Vietnam has become a watershed in our security commitment to the Third World, but there is less agreement on what the central “lesson of Vietnam” is. For a few persons, “no more Vietnams” means the virtual renunciation of our non-nuclear military commitments, but for most of us, including the President, the ambiguities and frustrations of Vietnam mean that we should be even more selective about our active military participation in the future than in the past.