GREAT achievements such as the collapse of communist totalitarianism in Eastern Europe and now the USSR deserve close examination. If we apply what American philosopher-journalist Herbert Croly called "trained and disciplined intelligence" to understanding how the victory was won, we may encourage further gains in the years ahead.The vanquishing of Soviet communism resulted in the first instance from the triumph of the ideas of the American Revolution. Now, at the time of their global ascendancy, it's easy to forget how lonely they were when Adams and Washington, Franklin and Jefferson first advanced them on the world stage. These ideas had a variety of sources: the English tradition of personal liberty; the ideals of the Enlightenment; and the Puritans' unwavering recognition of the fundamental worth and equality of each individual before God. But the combination of these root elements and the addition of the Founders' exceptional leadership were distinctly American. Even after individualist ideas won out in the former colonies, they were remarkably isolated in the world at large. In "The Old World's New World" (Oxford, 1991), historian C. Vann Woodward reminds us of how much of the European literature on the American experiment viewed it critically. For European tastes, the American Revolution was too much organized to meet the needs and claims of ordinary people. For a century and a half thereafter, the French Revolution, with its state-centered vision of how virtu e was to be obtained, occupied the passions of Europe's putative revolutionaries. It would be a long time before the "self-evident truths" that all persons "are created equal ... endowed with certain unalienable rights ... to Life, Liberty and the Pursuit of Happiness," would become dominant around the world; but their ultimate success underlies the great revolutions of 1989-91. Credit must go, of course, to the millions of people across Eastern Europe and the USSR whose commitment to individualism and freedom has been greatly enlarged and extended. Some of them engaged in memorable acts, but many others served simply by bringing heightened expectations of their due as individuals. Not long before his death, John Adams wrote that the "real American revolution" had taken place before the war with England commenced. It had been, he argued, a revolution "in the minds and hearts of the people ... a radical change in [their] principles, opinions, sentiments, and affections...." So, too, was the Russian Revolution of 1991. Economics also played a large part. As recently as the 1960s, many believed that economies built upon state ownership and central planning held the greatest promise - at least for "developing nations." But the catastrophic failures of the command economies are now understood. Individualist societies require individual-centered economies: No modern economy can work unless it is founded on the institution of private property. Two leaders have had special influence on the course of the recent transformations. One is Mikhail Gorbachev. Elevated by moderate reformers who had come to believe that the Soviet system could not be maintained unless greatly transformed, Mr. Gorbachev quickly went further in "restructuring" than many of his backers had intended - guided, apparently, by some idealized vision of a democratic socialism. Gorbachev's great historic role was first encouraging and then buying time for the revolution to occur in the minds and hearts of his people. The other leader is Ronald Reagan. Seweryn Bialer, a Soviet specialist with unparalleled contacts in the Soviet leadership, wrote in the mid-'80s of the extraordinary impact "Reaganism" was having on Soviet thinking. They had viewed the US as soft, complacent, a nation in moral and economic decline. By reasserting the vitality of American ideas and achieving what they had thought was the politically impossible task of rebuilding American military supremacy, Bialer argued, Reagan shocked Soviet leaders. H e convinced them that history was moving against rather than with them, and sent them scurrying down the road of change in a way that only hastened their system's collapse.