The distinctive thing about Mikhail Gorbachev as he approaches his convention, election, State of the Union and budget message all in one -- the Communist Party congress opening in a few days -- is that he is taking a page out of the book of Ronald Reagan. The imitation may not be deliberate, but the flattery is unmistakable. So is the challenge.

Recall the American circumstances of early 1980. The economy and foreign policy were stirring bipartisan dismay, and confidence in the political leadership was shot. Out of a kind of provincial obscurity came a presidential candidate asserting, in a much touted speech in Chicago, three new requirements of foreign policy.

The first, said Ronald Reagan, is "a clear vision of, and belief in, America's future," by which e meant faith in American capitalism as the engine of our progress and as a model for others. Then came a strong economy to provide, among other things, the sinews of military strength. Only then came "adequate military power." There was some hokum, but it was a sensible ordering of priorities, and six years later it holds up well enough so that one only wishes Reagan had better followed through.

Now the shoe is pinching in Moscow. It is the official Soviet consensus that the Soviet economy is dragging -- no demonstration is needed. It is the all but public Soviet consensus that Soviet foreign policy is dragging, too: socialism has no takers and free enterprise is moving ahead, Soviet increments of the 1970s (Afghanistan, Nicaragua) are being contested, the Americans have rearmed, and so on.

Out of provincial obscurity has come a newly assertive leader who is saying that the Soviet Union must urgently build up its economy at home in order to compete effectively abroad. Mikhail Gorbachev's program -- noisy discipline and discreet reform -- is different from Ronald Reagan's, but his purpose of revalidating socialism as a successful national and world system recalls what Reagan has tried to do with democracy and free enterprise.

The sharpest expression I have seen of the new Soviet line came in an address to the comrades of Turkmenistan by a Gorbachev sidekick, V. V. Zagladin. Accepting the burden of opening the eyes of puzzled provincials, he offered a catechism to make it all perfectly clear.

Why had imperialism moved from cold war to d,etente in the early 1970s?, he asked. "Because the Soviet Union had managed, on the basis of its economic achievements, to acquire military-strategic parity with the United States." A distortion -- the Soviet Union achieved parity not on its economic strengths but by robbing a troubled economy to build missiles -- but a revealing one.

Why, Zagladin went on, did d,etente give way to confrontation in the mid- 1970s? The Americans perceived that the Soviet Union was experiencing economic difficulties, he said, and tried to "apply the 'squeeze'." Again, an oversimplified analysis -- the Scoop Jackson Amendment squeezing credits was only part of the picture -- but an interesting one.

And why did the Americans suddenly decide on a Geneva summit in 1985? "Not least because they noticed that things were going better in the Soviet Union and that our development had begun to accelerate again." Partly true -- Gorbachev's take-charge manner had started making us nervous.

"We exert our chief influence on the development of events in the world through our economic policy," Zagladin concluded. Not through our party or ideology or power but through "our economic policy."

Gorbachev's turn toward his particular reformist economic priority was bound to be controversial. The labored manner of Zagladin's presentation suggests that some of the controversy stirred by it lingers on. My sense of the Kremlin play is that there are two "parties," not hawk and dove but hawkier-now and hawkier-later.

The hawkier-now school says: spend more on guns and keep pressing in the Third World, or else Ronald Reagan, who is still the same old wicked imperialist we always thought he was, will make us pay.

The hawkier-later group, including Gorbachev, replies: we needn't spend much more now on guns or for that matter on butter, but unless the Soviet Union modernizes its economic management and catches the world's cresting technological wave, our future prosperity and security will be in real jeopardy. In the interim, we won't be pushed around by Reagan, but we'll deal with him where possible, especially on arms.

Reagan's policy contributed substantially to the leadership gap that Gorbachev came forward to fill. Gorbachev's response at and after his party congress cannot fail to have a major impact on us.