America is changing hands.

In the 1980s the custody of the nation's leadership will be transferred from the World War II veterans, who have held sway for a generation, to a new set of men and women.

These newcomers -- the next ones in a leadership succession that goes back to the youthful men we call the Founding Fathers -- are the products of a set of experiences different from those which shaped the dominant American personalities of the past quarter-century.

They do not carry the memories or the scars of the Great Depression. They were not part of the victory over the totalitarianism in Italy, Germany and Japan.

The next ones who will take power -- the babies born between 1930 and 1955 -- were shaped in a very different time. Theirs has been a time of affluence and inflation, of extraordinary educational advance, and of wrenching social change and domestic discord.

They were immunized against the childhood diseases and exposed to endless hours of television. Their wars were fought in Korea and Vietnam, and if fewer of them returned as casualities, none returned as victors.

They saw America open the space age -- sending men to the moon, cameras and measuring instruments to distant planets. But they also saw the premature close of what their parents had called "the American century," as industrial obsolescence and resource dependency curtailed everything from the strength of the dollar to the use of the family car.

In their brief time, such familiar institutions as the two-party system and the nuclear family, with its male breadwiner, a housewife and two children, have become an endangered species.

Millions of the older members of this generation have seen their daughters "liberated," and thousands of younger members have spent nights in jail after some civil-rights or anti-war protest.

They have argued and sometimes fought with each other over civil rights, equal rights, the right to life and a dozen other causes. They have been through lunchroom sit-ins, Vietnam teach-ins and Watergate breakins. At one time or another, some of them have been "clean for Gene," and others have been keen for Proposition 13. They have embraced a good many heroes, and discarded most of them. Having come of age in the traumatic decade, bracketed by the murder of one president and the forced resignation of another, they have lost whatever romantic idealism they may have held about politics and government. Lamenting the lack of leadership, many of them have turned off and tuned out.

The men and women of this next generation have one other characteristic in common. Every president for whom they have been eligible to vote so far has been a man who was in uniform during Work War II.

In his own time and in his own way, each of those presidents has been a challenger of the status quo, an energizing force in the politics of his own community, state or nation. As befits a five-star general, Dwight Eisenhower entered politics at the top. But he still had to prove himself against the established favorite for the 1952 Republican nomination, Sen. Robert A. Taft of Ohio. He prevailed by mobilizing thousands of previously active voters to come out to Republican conventions and primaries, where they challenged and defeated Taft and the Old Guard.

That pattern has persisted. John F. Kennedy won the nomination for his House seat in a 10-man primary field, of which he was the youngest. He defeated an incumbent senator (Henry Cabot Lodge) six years later, and eight years after that beat the Senate majority leader (Lyndon Johnson) for the Democratic presidential nomination and outpolled the incumbent vice president in the general election.

Although Johnson is thought of, in retrospect, as an "establishment Democrat," he was a 29-year-old maverick kand the only New Dealer in a seven-man race for special election to the House of Representatives. He got to be senator only by beating out the governor of Texas, Coke Stevenson. g

Richard M. Nixon, as has often been told, answered an advertisement placed by Republican fund-raisers looking for a candidate bold enough to challenge a supposedly entrenched incumbent, Rep. Jerry Voorhis, in 1946, and he did the job for which he had hired on, against the odds. In his first Senate race, he had to beat the person who had beaten the incumbent in the primary. To become president, he had to beat the incumbent vice president.

Gerald R. Ford was the "Young Turk" Republican in Grand Rapids who took on the four-term isolationist Republican incumbent, Bartel J. Jonkman, and beat him in the primary. Later, he challenged and defeated two other Republican elders in his climb to the leadership of his party in the House, the post from which he was elevated to the vice presidency and then the presidency.

Jimmy Carter was the challenger and the underdog in every campaign he ever ran, from his first try for the Georgia state Senate in 1962 to his battle with former governor Carl Sanders in the 1970 gubernatorial race. In 1976, it was "Jimmy Who?" challenging almost a dozen better-known and more heavily credentialed Democrats in the primaries and then tackling the incumbent president of the United States.

In compiling this record of challenges and upsets, the World War II veterans have shown themselves tough and aggressive politicians. But their generation is also showing its age; its pace is slowing visibly. Eisenhower barely caught his breath between the time he left the service and the time he entered the presidency. For Kennedy, it took 15 years; for Johnson, 21 years; for Nixon, 23 years; for Ford, 29 years. Even with his delayed exit from uniform, Carter was 23 years a civilian before reaching the White House.

What was a fresh wave in our politics has become a stagnant pool of leadership, from which the voters pick their presidents with obvious and increasing reluctance. Voter turnouts -- which jumped significantly with Eisenhower and Kennedy -- have been declining in each successive presential election since 1960. The voters of today, in increasing numbers, question the relevance of yesterday's heroes.

It may be that the World War II veterans can extend their grip into the next decade. Carter's principal opponents in the election are the 69-year-old Ronald Reagan, who spent World War II as one of the "Culver City commandos," grinding out training and propaganda films while serving in the Army Air Corps, and the 58-year-old Rep. John B. Anderson, who spent World War II as a foot soldier in France and won four battle stars after D-Day.

If one looks more broadly at the positions of power in Washington, the pervasive grip of that generation is even more impressive. A majority of the leaders of the House and Senate, a majority of the Supreme Court and several of the members of the Cabinet are also World War II veterans, with many of the exceptions being even older.

And yet it is almost an actuarial certainty that at some point in the 1980s, the grip of the World War II veterans on the positions of power in American public life will be broken by the inexorable passage of time. By the end of the '80s, a youth who was 17 when the Japanese surrendered will be into his seventh decade -- not too old to be a president or a speaker of the House or a chief justice, but old enough to be thinking of retirement.

Meanwhile, a new generation is pushing forward, nudging toward the time when its members will take command. And they are, in many respects, both the echoes and the opposites of their parents.