DISCREETLY BUT distinctly, the administration has indicated to the Soviet Union that it's ready to do its part, if the Kremlin will do its, to try to break the impasse over trade and emigration that has soured Soviet-American relations since 1974. But the administration has to be sure it doesn't stumble into the political traps that had so much to do with creating that impasse.

The current stirrings began this way. Sen. Robert Dole (R-Kan.) is no great booster of detente, but he comes from a region with a great surplus of wheat. In the hope of opening up new markets, he proposed in effect to suspend the Jackson Amendment, which makes the trade-emigration link, to permit government credit-supported sales to certain Communist countries. The Agriculture Secretary offered his "personal" support. The State Department said it "would not object." The Office of Management and Budget cleared the proposal.

Then, however, some Jackson Amendment supporters objected that, in the words of one, the administration was "covertly crawling away from its stand on human rights." The Secretary of State wisely backpedalled, assuring Sen. Henry Jackson that the administration was not attempting to circumvent its obligations. Mr. Jackson, one understands, is pleased to accept that assurance. That's where things now stand.

It is not a glorious episode, but some instructive points have been made. First of all, the Russians can see that the Carter administration is willing to try to bring trade back into the Soviet-American picture. In contrast to earlier expectations, there seem to be few illusions left in Washington that trade can be a magic solvent of other tensions or that it can become very significant in strictly economic terms. But it is seen, rightly, as a useful aspect of a mature relationship.

Second, the Russians can now also see - as can the administration - that there isn't any way around the Jackson Amendment. Support for the pro-emigration purpose, of this measure has been, if anything, strengthened by the Carter human-rights drive. There is no value in bemoaning this any more. It's a political fact.

The amendment, however, is not the rigid instrument it is often thought to be. It includes, for instance, a provision that lets the President ask Congress to waive the amendment for a year if he thinks such a waiver will promote emigration. The amendment actually allows more flexibility than did the Kissinger-Jackson-Kremlin extralegal agreement that controlled emigration and trade for the brief period before it collapsed - as such a grotesque construction had to collapse - in 1974. We believe that Sen. Jackson would not allow his personal suspicions of the Russians to obstruct a quiet administration effort to seek a mutually acceptable way out of the current impasse. Mr. Jackson's relations with Jimmy Carter are as close, we note, as his relations with Henry Kissinger were strained.

In brief, there is a certain chastened mood in Washington on the trade-emigration question. The various parties are looking for ways to reshuffle the deck. That the Jackson Amendment, handled carefully, can be something other than a barrier to emigration and to trade and to better relations in general is being demonstrated in the case of Romania. We think it would be well worth the Russians' while to look at the question anew.