A DANGEROUS AND disruptive fuel shortage now afflicts the country - but what will we all, as Americans, learn from this experience? Remember, there was a previous shortage three years ago, during the Arab oil embargo, and the country didn't seem to learn much from that one. When this immediate crisis ends, will we all let the subject fade away again?

For all of the damage that the gas shortage has done over the past month, it has given the United States an opportunity.It has forced both government and citizens to focus on the urgent necessity of making changes in the way that we as a nation use and misuse fuel. The disputes over fuel policy run so deep, and the colliding interests are so large, that it's not really likely that much would have been done without it. The crisis at least makes action possible.

The country wasted the last opportunity of this sort. There were signals of coming trouble in national fuel supplies as early as 1972, but neither party wanted to talk about it in an election year. After the election, the Watergate scandals engulfed the Nixon administration and a desperate President was in no position to ask for public sacrifice. With no national leadership, the country responded only briefly and feebly to the challenge. We all continued to waste fuel and time - a very costly waste. It was a significant part of the price that this country paid for Mr. Nixon's re-election and the Watergate affair.

President Carter, in contrasts, is striking precisely the right tone - a big grim in this bleak season, but realistic and candid. Unlike the Nixon administration, he offers no hints that his magic wand can fix things up in a few days. Mr. Carter's whole point is that there is no magic wand - and never was. The present crisis may be over shortly, he warned last weekend, but the underlying shortages is permanent and it will get worse.

Mr. Carter put on his long johns and firmly set the White House thermostat down. There's good historical precedent for the long johns; people lived in the White House, after all, for many years before there was central heating. Most of our readers have had occasion over the past few days, we assume, to reflect on the truth that 60 degrees is indeed a spartan climate. But our grandparents' generation knew a good deal about getting through hard winters with a good deal less fuel than we customarily use today. They usually shut off part of the house, for example; with a couple of rooms up to 70 degrees, life went on pleasantly in houses where the temperature was otherwise in the 50s. In northern Europe, to heat bedrooms at all is widely regarded as hopelessly effete as well as grossly wasteful. That's one reason why European nations with living standards as high as ours get along with far less fuel.

The shortage at present is natural gas, but simply shifting to oil won't help much. The Federal Energy Administration points out that in the month ending in mid-January, this country was using 19.7 million barrels of oil a day. That's an all-time record, as they say on the sports pages. The previous record was in February, 1973 - the last cold winter before the embargo and the rise in oil prices. Since then, American oil production has declined - and imports have risen 48 per cent.

The country has now had two massive fuel shortages in three years. The pattern is obvious. If we Americans insist on unlimited fuel consumption, we can expect a steady succession of similar calamities. After all, nobody has suggested that this winter is the last cold one that we'll see.