I SOMETIMES HAVE the feeling that America is one vast playground and that the Americans are more and more using it like one. In order to use it, since it is so vast, they need a lot of gasoline. It is therefore a little absurd for any administration to suggest that it is only a few economies in the use of energy which it is asking of the American people, when the only thing that would have any significant effect would be a sacrifice of an entire way of life.

James Schlesinger said recently that, in the first four days of July, the American people used more gasoline than the entire land forces of the United States in the whole of 1944, the year they were most continuously in action around the globe. The comparison is melodramatic, but I am not sure it is as instructive. Private cars are using more gasoline in 1977 than army vehicles used in 1944. So what?

The first four days of July are a holiday weekend, when the Americans are hard at play. This has become a part of the American way of life. What is Schlesinger asking them to do? Give it all up, when they have just got it? And if he is not asking this of them, then what point is he making so dramatically?

A few days later, President Carter drew another comparison, just as melodramatic. He said that the peoples of several countries in Western Europe have as high a quality of living as the people of the United States, but that they consume, per capital, only half the amount of energy. Unfortunately, the first part of this statement is untrue. In no nation in Western Europe of comparable siz is there so extensive a "middle class," expecting and usually able to enjoy such a profusion of goods and experiences. The lower per-capita consumption of energy in Western Europe is based on a much narrower range of expectations for most people.

I WAS STILL pondering what Schlesinger and Carter had said when I went to stay for the weekend with some friends at Annapolis. It did not matter at what hour I sat at Horn Point - the Severn to my left, the Bay to the right - the boats sailed by from early morning until poast midnight: big ones and little ones, ketches and yawls, Lasers and dinghies, white jibs and colored spinnakers, a regatta that was endless.

All the boats could not belong to corporation vice presidents or to bank presidents or even to corporation lawyers. Some must belong to plumbers - they can afford them - and some must belong to . . . just the ordinary middle class of America; perhaps to a more affluent section of it than the rest, but still to kinds of people who in Europe would not think of owing a boat.

But the relative affluence of a considerable class is not my point here.What is interesting is how, in greater and greater numbers each year, Americans have taken to their playground, on beaches and in bays and in gulfs; on rivers and on lakes; in mountains and in desert and in the wilderness. Although the point seems to have eluded both Schlesinger and Carter, to get to his playground one needs a car, and, at least at the moment, cars are moved by gasoline.

Western Europe is a small and crowded peninsula. There are not very many places for its millions to go, and none of those places is very far away. There is not the immense coastline of America. There is not the variety of landscape on such a scale. There is not the same choice of climate in every season. Cyril Connolly once described a flight across the United States in the late 1940s, when planes still flew low and slow enough for one to look down on the countryside. He was amazed by what he saw, until he exclaimed: "All sense of European structure vanishes." We forget the difference too easily.

IT IS NOT ONLY of a leisure society that I am speaking - although the United States is its forerunner - but of a way of life that is peculiar to it, and which cannot be ignored if one is discussing something as personal as the per capita consumption of energy. There is more space in America, there are more places to go and more people able to go to them, so they use more gasoline. In fact, it would not have been surprising if in the first four days of July the American people had consumed more fuel than all the land forces in the world since Hannibal crossed the Alps with his elephants. But it would be as irrelevant as Schlesinger's figures.

Americans in their hundreds of thousands now sail in the great bays and esturaries of their country; they get there by car. They now backpack in the wilderness and in the mountains; they get there by car. They now kayak on their rivers; they get there by car. They now ski down the slopes of their country in winter and climb them in summer; they get there by car. They go to their beaches to swim or to laze; they get there by car. They go to the desert in spring and find its beauties; they get there by car. Even in the cities during the week, they go increasingly to tennis courts, swimming pools and golf courses; they get there often by car. And these activities add up to millions upon millions using their country all year round.

They need gasoline even to get to the places where they can then do what needs no gasoline. There is nothing more galling than meeting a backpacker in the mountains, enjoying his high with nature, complaining about the dreadfulness of a civilization that allows so many cars to make so many fumes and to use so much energy - and then watch him at the foot of the mountain calmly get into the Datsun which had brought him there, to drive back home in the serene and uncomplicated belief that at least his fumes have been for a worthy purpose.

But when this perverseness becomes the basis of the energy policy of an administration, it is time to utter a protest, because there is no way in which it can or should change the desired way of life of a nation. I happen not to engage in most of these activities, but I enjoy watching others enjoy them. So all that gasoline was spent in the first four days of July: Then I have to say to James Schlesinger, and through him to his President, that it was at least as well spent as by the armies of 1944.

The Americans are probably an unenvious people. They may and do have other faults, but envy is foreign to their nature. There is something wrong in using the energy crisis, real or imagined, to excite an envy of the enjoyments that others find in their own way.The environmentalists have always seemed to me to border on envy. Tie them to the puritanism implicit in Schlesinger's and Carter's remarks, and we will all be done, and allowed to use gasoline only when we are sent to fight wars. Let the tanks roll!