IT is one of the encouraging signs of the time that Walter Lippmann's essay on American foreign policy has become a nationwide best-seller. The jacket on the copy before me reports the marketing of 340,000, and doubtless by this time the figure has soared much higher. Those who assess the trends of the age should set that fact against the uproar of revolutionary spirits crusading anew for the ideals of 1917. Mr. Lippmann is an essential conservative, a thoughtful publicist not a demagogic candidate for office, and he stands far removed from the Lerners and Laskis. He is more concerned with saving the American Republic and Western Civilization than spreading an ideological gospel among political pagans not yet converted to the religion of ‘democracy.’ He knows, as all wise men know, that constitutional democracy, material progress, political and civil liberty flourish only in peace, and that peace depends on security. Therefore he seeks to discover what is that foreign policy which can be a ‘shield of the Republic’ and a safeguard for peace throughout the world. His book is a model of clarity and realism, composed in a truly Burkean temper of mind. To write upon this high level and at the same time reach a vast popular audience in a politically immature country, is a remarkable accomplishment. Probably no one but Lippmann could have done it.