Past mistakes do not bear repeating. It will therefore be a pity if - following the Siberian pipeline dispute - the United States and its European allies again find themselves slipping into a confrontation over the issue of East-West trade. Every diplomatic effort should be be made to avoid such a course.
The issue arises because the Common Market has protested US efforts to toughen controls on Western trade with the Soviet Union. It did so in a strongly worded memorandum delivered to the State Department. The Europeans are especially irritated about proposed US legislation that would enable the President to ban imports from countries selling goods to communist nations in violation of US trade sanctions - a law that would go farther than anything now on the books.
President Reagan's objective is clear. He is vigorously trying to curb exports to the Soviet Union which might contribute to Soviet defense capabilities and thus indirectly harm Western security. Certainly there is no quarrel that sensitive technology which is clearly applicable to the military should be brought under stricter export controls. A better job needs to be done here. There is no disagreement on that score. But, in the administration view, virtually everything - except American grain - helps the USSR and should therefore be carefully controlled.
So Mr. Reagan is asking for a number of things. He wants changes in the Export Administration Act, which comes up for renewal in September, including a ''contract sanctity'' provision which would allow US manufacturers (like American grain farmers) 270 days protection from a possible government embargo - a period of protection that would be too short for many companies. He also wants to add certain items to the so-called COCOM list of prohibited strategic goods (including oil-drilling equipment) which the Europeans believe do not belong there.
Ironically, the US business community and moderate Republican lawmakers are opposed to such legislation. Like the Europeans, they would like to see the Export Administration Act eased not tightened. One, because they want the United States to become viewed as a reliable supplier of goods (at a time when exports are increasingly important to a sturdy US economy) and, two, because they want to avoid the extraterritoriality issue (which was raised in the case of the pipeline). Their concerns are legitimate.
The point is that East-West trade cannot be measured solely in terms of US military security. The political and economic benefits from such trade need to be weighed as well. They, too, contribute to the West's security - by fueling economic growth, by giving the Soviet Union and its allies an increasing stake in world stability, by expanding human contacts, by fostering an interdependence of nations that acts as a counterforce to conflict.
The administration needs to reexamine its trade policies and philosophy. Congress had better look closely, too, and make sure that the lines of trade are kept open. It will not be lost on US legislators, any more than on West Europeans, that Mr. Reagan has offered to negotiate a long-term grain agreement with the Russians, thus overturning his own policy of Polish sanctions. Many will see this as highly inconsistent. Is grain not strategic?