House and Senate have been locked in conference since last spring over legislation to control exports of strategic goods such as advanced computers. Everybody supports the idea of preventing the Soviets and other similarly unwelcome customers from buying technology of military importance.

But the differences in approach turn out to be fundamental. The conference has now declared a stalemate and abandoned any further attempt to pass a bill this year. The reason is that the Reagan administration couldn't quite make up its mind, and its indecision exacerbated the conflict between the two houses of Congress.

That's not ideal, but it's no disaster. The basic law here, the Export Administration Act, has expired. But the president can continue to manage strategi exports under his emergency powers.

The legislation has been caught in a collision between two sharply diverging definitions of national security. Does security mean a meticulous screening of all exports of possible military significance leaving the country by any route that might conceivably lead to the Soviet bloc? That's been the Defense Department's position. The Commerce Department disagrees, arguing that screening on that scale would dangerously hamper and limit the export trade by which this country now earns a substantial part of its livelihood. According to Commerce, national security is best served by a strong economic base and the commercial incentives that keep technology developing rapidly.

Forced to take sides, the White House eventually backed Commerce -- but only halfheartedly. President Reagan never seems to have tried to impose his decision firmly on the Defense Department, or to have discouraged its vigorous campaign in Congress in behalf of restrictive export controls. The chairman of the Senate Banking Committee, Jake Garn, has been engaged in a stubborn and determined attempt to give the Defense Department broad authority to review export licenses. The House, with the nominal support of the White House, has tried to keep the Defense reviews limited to only the most sensitive technologies and the more suspect buyers. Now, after half a year of not very profitable debate, the conference has collapsed.

The Commerce Department is right, and better no bill than Sen. Garn's. The list of goods worth keeping from the Soviets is a rather short one. In the areas of computing, communications and industrial technology generally, very little stays secret for long. That is the nature of American society. Once new technology goes into widespread commercial use in this country, it is pointless to try to prevent it from being exported -- pointless and positively harmful to this country's industry. Security lies not in trade restrictions but in the kind of rapid technological progress that only a prosperous and open economy will generate.