In four years, the 12 member nations of the European Community, formerly known as the Common Market, are scheduled to take a major step toward becoming something like the "United States of Europe."

By 1992, they plan to turn Europe into a single economic entity by harmonizing all industrial and employment standards, coordinating some tax laws and financial market regulations, and getting rid of most customs and immigration laws.About the only obstacles between states will be that each will keep its own type of money, and of course, the language differences. Otherwise, borders between the European nations will largely cease to be barriers.

But the imminent tearing down of these barriers is causing anxiety in some places, both inside and outside of Europe. Certainly there will be an impact. Studies show that the increased competition caused when the borders open may cost 200,000 jobs at first as weaker firms fail to cope with the new competition. But it also may spur growth that will bring about 2 million new jobs.

Inside Europe, two distinct views have arisen. Trade unions, leftist political parties, and the poorer nations are afraid of what the internal shake up will mean. They want job guarantees, welfare benefits, the preservation of some trade barriers, and a larger government role in the economy.

On the other hand, conservative political groups and the business community -particularly in Britain and West Germany - want deregulation and as much of a free market economy as possible.

A free market economy would be better for the new united Europe in the long run. It could become an economic powerhouse rivaling or surpassing Japan and the United States. In fact, the Americans and Japanese are worried that the new Europe might raise higher trade barriers against the outside world even while tearing them down internally.

Yet that could lead to a mutually destructive trade war.

A powerful, prosperous new European community can provide stability and peace in the world. But nervousness over the change and over economic competition should not lead Europeans to take the wrong road into self-protection and economic short-sightedness.

It would be a shame if Europe were at last able to remove borders between ancient states on the continent, only to erect them against the outside world. That would simply recreate the old problems on a bigger stage.