The whole experience ought to have (but has not) taught Americans to cultivate deep regional knowledge in the practice of foreign policy, and to avoid being led by ideology instead of understanding. The United States should interact with other nations realistically, not on the basis of domestic political priorities. Very often the problems in distant lands have little or nothing to do with America's ideological preoccupations. Beware of men with theories that explain everything. Trust those who approach the world with humility and cautious insight.