Floyd E. Westbrook of Falls Church writes, "For some time now, I have been expecting to see some commentary in your column about the request of American automobile manufacturers for import restrictions on foreign cars, in order to help American producers over their current economic difficulties.

"Someone should tell our manufacturers that they have at hand the best means of imposing such restrictions on imports. All they have to do is produce a product that is better than the cars imported from abroad. The American consumer will take care of the rest. It would seem that all those overpaid clowns in big business have lost sight of the basic principles upon which the free enterprise system was supposedly founded. Maybe they should get out of the automobile business and go back to trying to build better mousetraps."

In recent years I have received many letters of this kind from readers who bought imported cars and felt no sense of guilt when American jobs were lost to foreigners. They were angry with American manufacturers for making large cars that consumed too much gasoline and needed too many repairs. They bought small imports to "get even" with an industry that had become deaf to their needs.

Before 1974, I did not agree with those in the protest movement. Until the OPEC oil cartel skyrocketed prices and curtailed supplies. I would not have bought a foreign car under any circumstances. The auto industry was basic to the American economy, and I didn't want to do anything to hurt it, or to cause Americans to lose their jobs.

I am aware that international trade is beneficial. I know that economic conditions in one nation affect, and are affected by, economic conditions in other countries.Whether they like it or not, realists must be One-Worlders. But my support for the elimination of international trade barriers was more theoretical than practical. In my role as a private citizen spending his money in a free marketplace, I chose to support American industry, not just in the purchase of automobiles but in all things. I wasn't fanatically committed to an undeviating Buy American program, but I was very much aware of the need to support home industry.

Today, my priorities and my views have changed. Shortages of energy and raw materials are now a clear and present danger.We must adjust our thinking to the changing times.

American automakers pushed their big gas guzzlers for one simple reason. There is more profit in selling big cars than in selling little ones.

We Americans like the big cars, we had the money to buy them and we had the gasoline to operate them. We wanted luxury, and Detroit got rich supplying it to us.

Gasoline had for years been far more expensive abroad than in this country. In fact, the high price of gasoline in Europe and Japan had been the greatest single factor in the development of fuel-efficient cars there.

After gasoline prices began to shoot up here, the public's desire to buy fuel-efficient cars increased far more than the ability of American manufacturers to produce them -- or, for that matter, more than Detroit's interest in going after the small-car market.

At first, our manufacturers airily dismissed the possibility that small cars would capture any significant percentage of the American market. By the time American producers began to take fuel-efficient cars seriously, they were in more trouble than they could handle. They were going to have to invest billions of dollars over a period of at least a half-dozen years before they could begin producing cars that would really compete with the imports.

By the time Detroit woke up, Chrysler was on the ropes, Ford was losing a ton of money on its American operations, and even the Big Daddy of the entire industry, General Motors, had to slash its dividend and prepare for hard times.

I can't blame the auto industry for trying to make money on big cars when the public wanted big cars and was willing to pay for them. But I can and do blame Detroit's top executives for being slow to recognize that OPEC had turned their industry upside down. People who are paid a million dollars a year in salary and bonuses ought to be smart enough to recognize a kick in the behind when they get one.

President Carter has been under severe pressure to relieve unemployment in our auto industry by banning or severely curtailing imports. He has had the political courage to resist. He knows that there is only one way to make sure that Detroit's geniuses concentrate on fuel economy and that is to keep the hot breath of competition on their necks.

The time to worry about bad times is during good times. Unfortunately for the auto industry and its employees and stockholders, the industry forgot to worry.