Alive, he would be scornfully dismissed by today's political opposition as "liberal, liberal, liberal."

Actually, many leading liberals of his time eyed him at first with suspicion. But based on the record of his two years and 306 days in the White House, President John F. Kennedy was perhaps the nation's last liberal hero.On Nov. 22, the nation will mark the 25th anniversary of Kennedy's assassination with solemn respect, remembering him through a nostalgic haze of myths and memories as a leader in a class by himself.

In the rotunda of the U.S. Capitol, a procession of Peace Corps volunteers will read aloud their letters and journals in a 24-hour vigil starting Nov. 21, reporting to the slain president who launched the overseas service program.

At Arlington National Cemetery, an honor guard from the Special Forces will lay a wreath in the shape of a green beret on Kennedy's grave. Kennedy popularized the elite unit, and his portrait hangs over the entrance to their headquarters at Fort Bragg, N.C.

And across the country, aging men who came to power with Kennedy and served under him will gather in small private reunions to recall the days of "Camelot" and reflect on how much has changed since his administration.

Some of those changes are particularly hard for them to swallow. There is sadness, anger and a touch of denial among some old Kennedy hands over the heave to the right in national politics.

Republican success depicting the liberal as a skunk at the picnic of American prosperity is dismissed by Harvard economist John Kenneth Galbraith as "one of the minor passing frauds of our time." Historian Arthur M. Schlesinger Jr. shrugs it off as merely "a quirk of the 1988 presidential campaign."

But other JFK-era liberals are more troubled. Theodore Sorensen, who served as White House counsel to Kennedy and helped write many of the president's most memorable speeches, including his inaugural address, worries that the political trend may be more profound.

"I'm afraid that in the last eight years, Ronald Reagan has had a tremendous effect on the political thinking in this country and succeeded in moving the spectrum to the right so that what was once conservative is now moderate, and what was reactionary is now conservative, and what was moderate, like Michael Dukakis, is considered liberal, and liberals are considered out of the mainstream by a great many people," Sorensen says.

No one today seems to be defending liberalism, but in 1960 John F. Kennedy was defending it, and defining it, in his own terms. When a weekly news magazine described him as "the farthest-out liberal Democrat around," Kennedy chose a gathering of New York's Liberal Party to deliver his response.

"What do our opponents mean when they apply to use the label `liberal?' " he asked. "If by `liberal' they mean, as they want people to believe, someone who is soft in his policies abroad, who is against local government and who is unconcerned with the taxpayers' dollar - then the record of this party and its members demonstrate that we are not that kind of `liberal.'

"But if by a `liberal' they mean someone who looks ahead and not behind, someone who welcomes new ideas without rigid reactions, someone who cares about the welfare of the people - their health, their housing, their schools, their jobs, their civil rights and their civil liberties - someone who believes that we can break through the stalemate and suspicions that grip us in our policies abroad, if that is what they mean by a `liberal,' then I'm proud to say that I'm a liberal."

In the tumultuous years since Kennedy uttered those words, the United States experienced a series of assassinations beginning with his own, a revolution in civil rights which gained steam and legitimacy under his leadership, the searing national tragedy of the Vietnam War, the triumph of his goal to put man on the moon, the shock of Watergate, the legalization of abortion, the flowering of the feminist movement and the pernicious influence of an expanding drug culture, and slippage in the nation's once domineering role in the world economy as international competition accelerates.

Along the way, the presidency itself lost its monopoly over foreign policy to an increasingly assertive Congress. And the president's domestic agenda has been vastly complicated by the fragmentation of legislative power and party discipline on Capitol Hill.

Despite all these changes, those who knew Kennedy well say they have no doubt that his approach to the problems besetting the United States today would remain a liberal one - activist at home, cautious abroad.

Kennedy did not believe in deficit financing and considered the $4 billion deficit he was running in 1963 to be an embarrassment.

To attack the budget deficits on the scale the nation faces today - when the annual interest on the national debt exceeds the entire federal budget under Kennedy - his former aides say he would likely propose deep cuts in military spending and almost certainly call for a tax increase.

"That would be very much in keeping with the call for sacrifice and discipline that rings through his first State of the Union message," Sorensen says.

"The notion that we are paying high taxes in this country is ridiculous," agrees David Bell, who was Kennedy's budget chief. "We are paying the lowest taxes in the world. We could certainly raise taxes without causing problems in the economy."

Defense spending "would be brought into line with the improvement in international relations," says Galbraith.

"Kennedy was very skeptical about adding more far-out technological weapons systems," says Roswell Gilpatrick, who served as deputy secretary of defense. Kennedy canceled the B-70 bomber, forerunner of today's B-1, and he killed the Skybolt program, which envisioned launching nuclear missiles from outer space.

But President Reagan's "Star Wars" research program is something that might well escape Kennedy-style budget cuts. Gilpatrick believes Kennedy would approve the costly research into a space-based missile defense shield "if it offered promise and he was convinced that the scientific community had a major consensus on that."

Sorensen said Kennedy, who forced Kremlin boss Nikita Khrushchev to pull nuclear missiles out of Cuba in a tense confrontation that led to a massive Soviet military buildup in subsequent years, would adopt a posture of "hopeful vigilance" toward Mikhail Gorbachev's efforts to reduce superpower tension. "He would not have relaxed his concerns about Soviet behavior internally or externally, but he would have welcomed general reform and looked for ways to further it."

The lessons he learned at the Bay of Pigs, the disastrous Cuban invasion set in motion under Eisenhower but probably made worse by Kennedy's ambivalence and hesitance, would steer him away from military adventures like supporting the Contra rebels in Nicaragua, say his former aides.

"Remember, Kennedy's approach was to try to work out relationships on the basis of economic progress and negotiation. That's what the Alliance for Progress" was all about, says Gilpatrick, recalling Kennedy's major Latin American initiative.

Kennedy would have "no magical solution" to offer for freeing American hostages in the Middle East, Sorensen says. "He wasn't a believer in magical solutions. But many of the underlying problems that give rise to terrorism were those he addressed as president _ poverty and injustice in the Third World, and the need for the United States and other developed countries to pay more attention to that poverty and injustice."

Kennedy, like Reagan, was a free-trade advocate, Sorensen recalls, "but he was not beyond practicing a little selective protectionism where necessary."

Kennedy worked out "voluntary" agreements with textile exporters to limit their market share to protect domestic manufacturers.

Among the changes in the presidency that former members of the Kennedy administration marvel at today is the growth of the White House staff.

The Kennedy White House was a mom-and-pop operation compared to the corporate sprawl of the modern presidency.

Operating with no chief of staff, Kennedy's senior aides, about a dozen, all reported directly to the president. Counting doormen and housekeepers, there were 429 people on the payroll in Kennedy's White House, according to the highest estimates.

Reagan's White House staff today totals 3,366 full-time workers, along with another 2,500 military personnel who support the president's activities part time, according to Bradley H. Patterson Jr., who wrote a book on the presidential personnel entitled "Ring of Power."

"The president's wife now has a larger staff than Franklin D. Roosevelt had when he fought World War II," says historian Schlesinger.

The White House staff seems to have become an unwieldy bureaucracy in itself, resulting in a slowdown in presidential decision-making, says Gilpatrick.

"Kennedy was so much involved in the day-to-day running of his government," Gilpatrick recalls. "I'd be on the phone with him and see him many times a week. I talk to people in the Reagan administration who don't see the president for months on end. He has over-delegated the functions of the presidency. What a new president will do about that, I don't know.