THE slide in US-Soviet relations since last fall's Geneva summit shows no sign of stopping. For his part, President Reagan has to establish more-central control of his Soviet, summit, and arms control policy. This is the starting point for action, much as it has been through the first five years of the Reagan administration.
How the Soviets respond is another matter. Secretary of State George Shultz is understandably flummoxed by the Soviet leader's resort to ``public diplomacy'' in recent weeks -- as in Mr. Gorbachev's bid last weekend for a quick summit in Europe on nuclear testing. Mr. Shultz hopes to get a better fix on Kremlin thinking, about the delay in setting a date for the promised Gorbachev visit, among other things, when former Soviet Ambassador Anatoly Dobrynin returns to Washington this month for his farewell calls. But private channels could prove no more fruitful; Mr. Dobrynin may not be able to deliver, with uncertainty growing on both sides over the other's basic aims, intentions, and readiness to reach agreements.
Mr. Shultz is right that the confrontational rhetoric and public gamesmanship -- the ``politics of theater'' -- have to abate if preparations for a summit are to go forward. But the administration itself remains split on the issue. Some administration forces have been pushing, with success, an anti-Soviet Nicaragua policy; shipment of Stinger missiles to Afghanistan and Angola; and uninterrupted United States nuclear testing, so critical to the development of a nuclear-powered X-ray laser for the President's Strategic Defense Initiative.
We prefer to think that the jury is still out on the prospects for a second, and third, superpower summit, and on an arms control arrangement. There still are individuals in the administration who want things to happen in a positive way. Shultz's efforts to meet with a Soviet counterpart, which he finally succeeded in doing in Stockholm, are one indication. Mr. Reagan seems genuinely to want to arrange another summit. For the moment it is the Soviets who are hanging back, and confusion persists in US analytical circles over why this is so.
The administration's management style needs attention. After the September summit, the President apparently gave no clear guidelines of what he wanted over the next year, and what he did not want, on the crucial US-Soviet agenda. He changed national-security advisers; White House chief of staff Donald Regan now seems to serve as spokesman for the National Security Council. That the administration is still debating its decision on abiding by the SALT II treaty (whether to take two Poseidon submarines out of service when a new Trident sub begins sea trials in May) shows how long the most basic questions can linger under debate.
In the absence of a definitive, coherent policy reaching the President's desk for decision, individuals in the Defense Department, Arms Control Agency, and State Department can speak publicly, throwing out contradictory versions of White House intent. Bureaucrats prolong the confrontational status quo by making sure policy does not reach the President's desk in coherent form or sidetrack issues in the form of review groups.
The Soviets can see that President Reagan has the power to get an agreement through his Republican-controlled Senate. The difficulty seems to lie in the absence of a third force -- a Henry Kissinger type of conceptualist and coordinator -- to overcome the ambivalence the President himself shares with his administration's factions.
That ambivalence continually surfaces: The Soviet mission at the United Nations is cut, but action is postponed for six months. And so forth.
Inconsistency leads to questions on sincerity. There is likely room for only one strong public figure in the Reagan camp, the President himself, given the long-established mythology of the Reagan style. But someone must assume responsibility for the superpower slide before valuable opportunities are lost.