THIS DECADE of the Fifties, newly accessible to us through the manufactured nostalgia on television, is showing on split screens in many living rooms, including my own.

The parents blink in confusion, watching our youthful nights at the drive-in, ogling the car hops, recycled as popular romance for TV. Hanging out, it was called. Many of us tend to recall how dull and painful it seemed at the time.

Meanwhile, our children listen to the jerky song lyrics from that era and, doubtless, they marvel at the innocence of olden times.

Earth Angel. Doggie in the Window. Ragg Mopp. Love Letters in the Sand. Cry. If I Knew You Were Coming, I'd Have Baked a Cake.

Can you imagine young people slow-dancing, cheek-to-cheek? In a well-lighted school cafeteria, with the tables pushed back and dozens of parents hovering nearby? The jukebox crooned:

See the pyramids along the Nile/Watch the sunset in a tropic isle/Just remember, darling, all the while/You belong to me.

This was befire everbody got liberated. The many chaperones were present to protect us from making what was known as "the biggest mistake of your life," the one many of us were trying so earnestly to make.

Oh, Yes! I'm the great Pre-TEN-der!

The high school football team, I remember, used to sing the "Great Pretender" in chorus in the showers every day after practice. The coach cried that season. We won three games in a row by a single point and he could not stand it. So we lost the rest of our games, by comfortable margins.

In college, we rioted. We blocked traffic with out bodies, taunted the policemen, hooted and hollered and did the petty vandalism associated with those happenings. It was springtime and, specifically, we were inspired by Bill Haley's Comets and their new record, "Rock Around the Clock." It was an apolitical riot, in homage to the rising of the sap.

So we were labeled by simple brackets, just as suceeding waves of misguided youth were: the silent generation. No ideas, no worthy passions. We were, as the kids might say now, laid back.

Reasonably accurate, as label go. If you were optimistic and dull-witted, you believed in Dick Clark's American Bandstand and Pat Boone's virginity. If you were restless and sullen, still undefined, a sensitive flower in a callous world, you tended to plan ahead on the model of James Dean. "Rebel Without a Cause." Alternately, Marlon Brandor or Elvis.

The sophisticated version of these fantasies was Jack Kerouac's On the Road, which was widely scorned at the time for its artistic flaws, but Kerouac opened wonderful new possibilities for twisted youth: malaise, anarchy, midnight visions, long journeys in old cars. Kerouac was an authentic prophet of the cultural choices that lay ahead, the lost children in Babylon searching for an appropriately tragic ending.

The nostalgia productions, therefore, do have a shallow accuracy, in depicting the trivial feelings of that decade. The mellow silliness, the orthodoxy of wholesomeness that suffused everything. Happy days, indeed.

But of course the nostalgia misses the mocking laughter underneath. It ignores the tremors that all of us felt, the dizzying effects, a king of leaping forward that American society went through in that period, unaware of the consequences. Those effects still shake us, though still not understood.

The melancholy feeling in the Fifties, very strongly expressed behind the orthodox cheering, was like the closing of Last Frontiers, the pathos of cherished myths buried, the way American yeomanry shuddered in the 1890s when people realized that the West was over, done, settled. In the Fifties, people had to face up to the certain truth that, for the future, nearly everyone would work and survive, succeed or perish on the terms of very large organizations, the corporations. This was not a new fact, of course, but it was newly understood.

Remember Sloan Wilson's popular pot boiler, The Man in the Gray Flannel Suit? Or Executive Suite? Can a man sell soap without losing his soul? There were new rules, new pitfalls, new conceits and complications to the American dream, a new price to be paid for the fabulous prosperity of that era. William H. Whyte described the compartmentalized dimensions of modern life in The Organization Man. David Riesman pondered the social costs of life set in little boxes in The Lonely Crowd. Many of us prefered instead, to read On the Road and dream about James Dean endings.

Thus, on this mythic level, the world seemed suddenly cramped and finished and impossibly complex. An immovable reality too awesome to challenge, too gargantuan to recognize human choices. (This defeatist judgement was proved to be reasonably valid when tested by a later generation which hurled itself against the wall and discovered, wow, the wall didn't crumble.)

Yet, without any of us grasping it at the time, the Fifties did something quite different to all of us: it enlarged the human reach. At a very fast tempo.It wiped out the old dimensions of human discourse, our sense of distance, even the boundaries of nations. How could anyone have known?

Has anyone who us under 35 years of age ever heard of the COoaxial Cable? The Coaxial Cable was very big in the Fifties. It was the linkup, the magic wire that plugged all of us into same lighted box, a continental village laughing in unison at Milton Berle. In 1951 Harry Truman gave a speech in San Francisco which was carried - live! - by ninety-four TV stations across the country, the first truly national telecast and, one might say, the first event of the modern presidency.

Today's children will be scolded, perhaps even punished, for drugging their minds excessively on the idiot TV cartoon shows. But their parents have suppressed the memory of racing home from school - as grown children, as teenager - to watch Mickey Mouse and Howdy Doody. It was, after all, a new miracle.

The satellites came along a few years later and made us into the global village. Instant war, famine, coronations, Olympic games in our living rooms. People were not as stunned as you might think when the Government announced that it was going to make a metal "basketball" whirl around the globe. People tended to believe the Government in those days.

The space vehicles were discussed at that time solely in terms of Cold War rilvary, catching up with Sputnik, but the significance was in our new perspective of the world: looking back from space, we could never see ourselved quite the same."

"This island earth," Archibald MacLeish called it later. The children's program on TV called it "the big blue marble." The Fifties launched this consciousness, with deep political implications for the future. How will grown-up children, who grew up with the "Big Blue Marble," react if the bugles sound again for what the White House experts like to call a "notional war"? They will ask why, I think. They will want to know whose notion it is.

THis Fifties defeated national boundaries in more direct ways. The Hydrogen Bomb - Eniwetok, November 1, 1952 - raised a permanent cloud which floats over all the globe together. Is the mother's milk in Lapland conditioned in some way by experiments in the Nevade desert? Possibly it is. Has human survival been reduced to a mad game of diplomatic crapshooting, in which a nation demonstrates its strength by threatening to obliterate the species? Maybe it has.

A few years after the bomb, the first squadrons of intercontinental rockets were deployed, both here and there, enduring that, if it comes to that, nuclear destruction will be shared and shared alike, ours and theirs.

Since then, the Pentagon has shown a capacity to elaborate endlessly on its nuclear weaponry but the first truth about those rockets, demonstrated in the late Fifties, has not been altered: the Department of Defense can no longer attack. There it is. So simple and obvious. Yet this fundamental truth is still regarded as faintly treasonous.

The tempo of change in the Fifties was even faster than these fundamentals convey. A simple matter like dialing long-distance phone calls represents a leap forward in technology that changed human distances.

The interstate highways did the same thing (launched under a ludicrous rationale of "National Defense," as though superhighways to move its tanks from city to city when the Russians arrived at our shore).

Jet airliners gave us even more time and distance. It seems as though we have been flying on jets forever (that luckly half of us who can afford it) but the first U.S. commericial jet service was in 1958. New York to Miami. Fun in the sun.

These various miracles of modern living were disorienting, yet they were eclipsed by the national paranoia. Fear was the program. The nation experienced fabulous prosperity in the Fifties, awesome economic growth, obvious preeminence in everything from cars, home freezers, TVs, to our national product nearly doubled, a fat time of big cars with tailfins.

And yet the country was a society of insecurity. The political obsession was creeping with communism, spies, subversives, defense pacts and all that. Twenty-five thousand Americans died to defend the dictator of South Korea. When Khrushchev predicted outrageously that the Soviet standard-of-living would surpass Amrican's by 1970, many zealous patriots believed him and went out to search for more spies.

Listen to this: the Secretary of state actually proclaimed. as national policy, that we would go to the "brink of war" whenever the Reds poked at us. What he said was: "The ability to get to the verge without getting into the war is the necessary art."

It sounds wacky now. Unfortunately, some of John Foster Dulles's successors were less artful than he. They went to the verge, then over the brink, any you know the rest. Many former Mouseketeers were killed or wounded.

Why? The historians and artists are plowing into the obvious question: why was America so insecure in the Fifties at the very time it was becoming so strong? Maybe all of those technological changes had something to do with it. Maybe it was that shuddering feeling at the closing of the last frontier, a vague emotional consensus that someone must be blamed for complicating life so suddenly. Therefore, let us blame the Commies.

There is another less onvious question: Why do we still feel so good the Fifties, when we know that the nostalgia ignores all that fear, trauma, restlessness?

My own hunch is that the leadership of President Eisenhower had a lot to do with this. Ike was a genuine hero who did not demand too much of us (the last laid-back President, if you will). He could blandly look the other way, like the rest of the nation, when something truly fundamental approached him, such as the Brown decision to abolish segregation, such as Martin Luther King Jr. launching the civil rights movements.

Eisenhower smiled so openly. He preached occasionally but this language was unadorned, not too stuffy, and his sermons were mellow platitudes from the past. It is often said that Ike ignored the festering social problems, that he tried to hold back history, which is true, which is perhaps why people remember him so fondly. It is said that he was a boring Preseident and, certainly, he often seemed bored with the job. It is seldom said, however, that Ike was the last President to leave the White House with his popularity still substantially intact.

This is another form of nostalgia, of course, the fond remembrances of Ike. Looking back through the split screen, I can say that none of us thought about him that much when he was President. Certainly, none of us imagined that someday we would recall his virtues and reflect that his mellow, simple style must have passed on, too, with those simple, happy days.