IN HIS PERSON as in his career, Sir Anthony Eden, dead now at 79, was the quintessential 20th century Briton. "Upstairs" born, he fought bravely in World War I and, as though to spare Britain war ever more, entered diplomacy, becoming foreign secretary at age 38 and impressing a generation with the timeliness and fervor of his warnings about fiscism. His resignation in 1938, to protest appeasement, completed the establishment of hismoral credentials and also ensured him the patronage of Winson Churchill, who soon brought him back and made "my trusted deputy" his heir apparent. Sir Anthony became a devoted and expert promoter of Anglo-American unity - for military purposes during the war, for purposes of British rehabilitation afterward.

"Don't, for God's sake, play a double game," his father had cautioned. Yet, becoming prime minister in 1955, he did just that. He abandoned the faith in negotaition by which he had set store as a diplomat, jettisoned his career-long reliance on Atlantic consensus, and plunged into the crisis that wrecked his career and confirmed the demise of Britain as a world power. President Nasser had nationlized the Suez Canal. Positing a "Hitlwer of the Nile" who could not be appeased, Sir Anthony, with France and Israel, invaded Egypt. President Eisenhower, professing moral outrage and perceiving disaster, protested. Crushed by the awareness that Britain no longer possed the means to conduct an independent policy, Sir Anthone retreated. Soon he resigned.

Sir Anthony was of a time - the last time - in Britain when men acting in the name of a certain class tradition, one with a moral force, could expect to be raised to national leadership largely without challenge. In and after World War II, he served that tradition brilliantly; in Suez, he violated that trustand thereby contributed in no small measure to the breakdown of respect for his class. He was also of a time when Britain placed such importance on its own international role that a national leader could be selected chiefly on the basis of his supposed command in that field of policy. It was the final irony of Sir Anthoney's life that, byhis failure at Suez, he closed out that tradition, too.