INEVITABLE REVOLUTIONS: The United States in Central America by Walter LaFeber (W.W. Norton: $22.95; 452 pp.). Henry Cabot Lodge, then U.S. ambassador to the United Nations, said it in 1959 while briefing Eisenhower's cabinet about the threat posed by Castro: "We should focus attention on the Declaration of Independence rather than on the Communist Manifesto." Lodge's advice was sound then, and remains so today, but as historian Walter LaFeber demonstrates in the course of this authoritative book, it is advice our nation has proved incapable of following. "Inevitable Revolutions," an updated version of a title first published in 1983, is a thorough thrashing of Washington's diplomatic track record in Central America, and it's an indictment based on the belief that U.S. politicians, of all stripes, are better students of money and might than of history. The basic problem, writes LaFeber, has been the continuing refusal of the United States "to confront either the economic or political results of its system in Central America"--a system instituted 150 years ago that presumed Nicaragua, El Salvador, Guatemala, Honduras and Costa Rica to be fiefdoms from which the United States could extract resources and to which it could dictate terms. LaFeber's argument sounds dismayingly partisan, until you read the book and come to see how deeply the United States has shaped Central American history--through the banana and coffee trade, through a score of Marine landings between 1898 and 1920 alone--to suit its own interests.