WHAT DO TROY, Renaissance Rome, the English parliament of the eighteenth century and America in the 1960s have in common? Each had leaders who led their countries to disaster, and each is the subject of a chapter in historian Barbara W. Tuchman's new book The March of Folly.

Tuchman is no newcomer to popular history. Her previous works have encompassed subjects from the Zimmerman telegram of World War I to the life of the French nobility in the middle ages, and her anecdotal style has captured the interest of enough of the general public to win her places on the New York Times bestseller list.

Some "serious" historians have criticized Tuchman for selling out, saying she narrates history without drawing any conclusions. The March of Folly, however, should satisfy both camps. Tuchman packs her writing with tidbits--scandalous, racy, funny, and troubling--about leaders from Pope Alexander VI (1592-1503) to Lyndon B. Johnson, while at the same time drawing parallels between the ages and generalities from the events.

The prototype of tales of political folly, Tuchman says, is the story of the Seige of Troy. Why would the Trojans suspect nothing when their enemies for 10 years, the Greeks, withdrew suddenly in the middle of the night and left a huge wooden horse behind them? The Trojans neglected even to examine the horse before tearing down the gates of their city to bring it inside.

Could their mistake be excused on the grounds that the gods were against the Trojans, and backed the Greek warriors hidden inside the hollow wooden statue? The second folly Tuchman examines, however, will allow no excuses based on the ill will of Zeus, Hera, or Athena--it involves the six popes of the Catholic Church who held office from 1470-1530, and whose mismanagement led directly to the Protestant secession.

The condition of the Catholic Church during the Renaissance papacies is enough to leave Jews, Moslems and Protestants snickering and to send Catholics scurrying for their rosary beads. The indulgences of Innocent VIII, the depravity of Alexander VI (Rodrigo Borgia bought himself the papacy and used it to benefit his illegitimate children), and the wars of Julias II left Rome bankrupt. When Cardinal Giovanni d'Medici became Pope Leo X, declaring "God has given us the papacy--now let us enjoy it", he was desperate for money and decided to sell the only thing he could--pardons. Full-scale simonry continued throughout the age, with indulgences being sold at church alters.

The Renaissance popes ignored the increasing alienation of the intellectuals, such as Martin Luther, who were ethically troubled by the trafficking, and the populace, who for purely financial reasons disliked the practice. They also overlooked the German and Spanish forces that marshalled outside Rome in 1527 and attacked the city of St. Peter. The combination of factors, however, proved too much for the system. Materially and spiritually bankrupt, Rome surrendered to Charles V and could not prevent the Protestant secession.

The next incidence of folly was also caused by deafness to grassroots sentiment. Perhaps the Renaissance popes can be excused, Tuchman argues, surrounded as they were by the trappings of their office. But British parliamentarians, who pioneered the system of representative government, should have listened to the "common man" when he called from America for representation. Americans protesting the Stamp Act had no ideas of breaking away from English rule; they just found it unfair to be taxed without a voice.

The American Revolution did not erupt overnight. A long series of protests, such as the Boston Tea Party and the Harvard graduation of 1768--all the graduates wore clothing made of American cloth--should have given the House of Commons ample warning of the unrest. Yet prejudice against the colonists and their abilities, and the false sense of superiority in the British government, created the blunders that caused the American revolution, Tuchman argues.

Tuchman's final example is one of the most extensive government follies in history America's long involvement in Vietnam, which began with aid to French troops in 1946 and ended with 45,000 American casualties.

Once again, prejudice contributed to the folly. Many people felt the Vietnamese were just too weak to fight back, or that the superiority of democracy over communism would lead to immediate victory.

Perhaps the greatest force was inertia. The Air Force insisted the bombing be kept up because it had always been done that way, even when studies showed it was no help at all. President after President campaigned on an anti-war platform, only to keep the troops in the jungles for a little bit longer in hopes of a final victory. Politicians are always reluctant, Tuchman observes, to "cut their losses and pull out."

Unlike her previous books, which tend to degenerate into a string of unrelated, if interesting, incidents, Tuchman binds the four examples together with common factors. Starting with the original Laocoon, a citizen of Troy who felt that various natural phenomena promised doom, Tuchman goes on to find modern-day Laocoons. John Kenneth Galbraith, Arthur Schlesinger Sr. and McGeorge Bundy. Moreover, each instance of folly described by Tuchman builds on the one before it: modern leaders repeat--and expand--the mistakes of their predecessors.

The March of Folly not only provides historical insights but also provokes questions about our present political leaders. George Humphrey, Secretary of the Treasury under President Eisenhower, warns his superiors that "disaster would result from 'a military program that scorned the resources and problems of our economy'" by increasing the budget deficit. Advisors such as Edwin O. Reischauer see tragedy in the fact that the West "allowed the Indochinese nationalism to become a Communist cause." In the follies of the past we see shades of the policy of the present. Tuchman laments the failure of the world's past leaders to learn from their predecessors. The March of Folly is, in fact, a plea to stop the march of folly