Economics having been the big issue, Reaganomics is the obvious big loser in last Tuesday's elections. But a second casualty, however innocent a bystander in the minds of voters, may well be what slim prospect existed for progress on a central issue of foreign policy: the U.S.-Soviet relationship.

For reasons having to do as much with Soviet internal politics as our own, it now looks possible that the world's two great superpowers could remain locked in glacial confrontation for the duration of Ronald Reagan's first term.

The president's current condition is nicely captured in a phrase used by Gen. Charles de Gaulle to explain why he was so hard to get along with as wartime leader of the French. Ronald Reagan is now "too weak to bend" -- having already struck the tough-guy pose as a calculated strategy.

With Congress, of course, he may be forced to bend, not only on economic issues but on the huge defense spending increases that underpin his foreign policy. But that will serve only to make him all the less willing to risk miscalculation by bending in ways that might invite a little easing of the tension, perhaps even limited accommodations on both sides.

And if Ronald Reagan can't bend -- if he can't bring himself to abandon the chest-thumping and jungle yells of his "Me Tarzan" approach to the Soviets-- you can be pretty certain Leonid Brezhnev (or whoever is running things in Moscow) is not going to risk rejection, and repudiation at home by making the first move. Soviet internal politics are also in transition and threatened by the paralysis of power struggles.

It is intriguing to speculate on how or when (or at whose hands) the long-awaited succession to Brezhnev will come about. But a consensus is building among Soviet analysts in this town that, as one of them puts it, "the preparations are well advanced."

Nobody's got a timetable. But there is considerable consensus on the likely sequence of events: a new Soviet leadership, emerging in two phases, as cronies and familiar figures give way, in an atmosphere of some turmoil, to whoever turns out to have the staying power for the long term.

"We are talking about the mid-1980s or even later before we may really know where the Soviets are heading," says one expert. As do others, he figures the first impulse will be to "muddle through" while consolidating power before making the tough, perhaps even radical, choices necessary to reconcile the failures of the system and the crisis in the economy with huge defense outlays and an ambitious global reach.

In the period leading up to Brezhnev's departure from the scene, and for a considerable shakedown period thereafter, the Soviets are unlikely to be up to the effort -- to the risk -- of big changes or new initiatives. And this owes much to the way almost any collection of Soviet leaders would read the Reagan administration's approach: as unalterably intransigent to the point that any Soviet maneuvering for accommodation would carry with it a politically unacceptable danger of rebuff.

"The Soviets have given up on Reagan," says one analyst here. "For them it's no-win. If they play rough, they are to be punished. If they show weakness, Soviet communism is consigned to the ash heap of history."

For its part, the administration acts as if it has given up as well -- at least in being willing to spell out some basis for a safer, sounder U.S.-Soviet relationship. Rather, the emphasis is on somehow forcing a change in the Soviet system; on achieving military superiority; on name-calling and icy indifference to anything short of capitulation to American terms.

If the administration could find logic in this approach before Tuesday's returns rolled in, the weakening of the president's command in Congress would seem to make it even more logical to stay with it now. "It will be a cold winter," John F. Kennedy said after his meeting in 1961 with Nikita Khrushchev. The same may be said for the outlook today.