NOT SINCE NAPOLEON has there been a more disorderly retreat from Moscow that conducted by Secretary of State Vance last weekend. In the presence of the journalists with the party, he and his aides met Soviet rejection of their strategic arms control proposals with a tight upper lip and a show of determination to keep on negotiating. The word nonetheless shortly leaked out that the Vance party felt the United States had grievously miscalculated its baptismal approach to the Kremlin by presenting too ambitious and demanding an offer in too public and blunt a manner. Mr. Vance may not be responsible for the leaks. But if his views have been accurately portrayed, he is almost certainly making a dubious and gratuitous self-appraisal with very unhappy implications. The thrust of it is that the Russians should be excused for their negative response and the United States should eat crow and come back to the table with proposals more suitable to Soviet taste.

Needless to say, the Russians lost no time seconding this motion. They have been pouring into every available American ear in Moscow laments about the Carter administration's negotiating style and, in particular, its supposed tendency to abandon commitments made by the previous administration. Pravda intoned solemnly on Sunday: "It is now up to the United States." It is a formidable performance but our own eyes are dry. The charge of inconsistency is simply unfounded. Mr. Carter offered the Russians essentially the last Ford proposal, a relatively modest measure that they had rejected before and that they rejected again last week. As an alternative, he offered a much bolder proposal for genuine reductions of offensive strategic arms.

There is a more plausible explanation of Soviet policy. It is this. Mr. Carter posed the Russians some tough choices. They chose not to respond. One can think of various explanations, including the hope that by hanging tough they could coax out a sweeter offer without making any concessions of their own. Another possibility is that Leonid Brezhev's illness may have induced in the Soviet political system an inability to take large and important decisions - something similar to the condition that afflicted the American political system at the height of Richard Nixon's Watergate immobilization.

This is not to say that the American tactics were flawless. Quite the contrary. As we suggested earlier, Mr. Carter may well have laid on the human rights line too thick. Though the Russians had adequate forewarning, the scope of the proposals Mr. Vance brought to Moscow probably did startle them. Certainly there were no grounds for expecting quick Soviet approval. But these are hardly the determinants of Soviet policy in an area so crucial as strategic arms. To confuse the expressions of a Soviet manner with a failure of American substance is injustified. Analytically it is questionable and politically it is needlessly damaging to assert that American "miscalculation" was somehow the engine of a great diplomatic debacle.

Fortunately, the situation is not irredeemable. The essence of the American position - to trade limits on the American weapons that Moscow most fears for limits on the Soviet weapons that Washington most fears in order to hold a strategic balance - remains sound. The details of it as presented in Moscow are hardly cast in concrete. The Russians may need a while to decide to look closely at it. The United States should use the interval to regain its internal balance and to contemplate the tactics best suited to gain a fair hearing for an approach that is, we believe, firmly in the mutual Soviet-American interest.