Those sitting in the Kremlin must be baffled by the contradictory signals coming out of Washington these days. First they hear the President delivering a conciliatory speech on East-West relations and proposing nuclear arms reductions. Then they listen to national security adviser William Clark enunciating a new ''national security strategy'' that commits the US to a confrontational policy toward the Soviet Union and that seems to call for a rollback of the Soviet empire.
The people of Western Europe and the United States may be no less puzzled. On the face of it the Reagan administration has moved toward the center on foreign policy. It is finally preparing for strategic arms negotiations with the Russians (Secretary of State Haig disclosed that Leonid Brezhnev has responded positively to the President's letter urging early talks). It has declared itself willing to sell more grain to the Russians. It is also dropping its opposition to the gas pipeline from Siberia in return for European agreement to curb future Soviet credits. The ground is thus being laid, it would seem, for a more pragmatic approach to US-Soviet relations - an encouraging development.
Why, then the ''Clark doctrine?'' That is, a US policy of compelling the Russians to turn their attention inward, playing up Soviet economic weakneses, moving ahead with a massive American military buildup, stepping up arms aid abroad, and opposing Moscow in every way possible? Perhaps the President is worried about appearing too soft on communism and therefore is reassuring his most conservative constituents. Perhaps this is an effort to put the best ideological face on what seems to be a gradual shift to a more realistic US policy. And perhaps there is less in the strategy than appears on the surface. Mr. Clark does seem to have pulled back from the even tougher stance of Defense Secretary Caspar Weinberger who thinks the US should be prepared for fighting a global conflict on all fronts. ''We can't,'' said Mr. Clark, scaling down that objective.
In any case, Mr. Clark's speech at Georgetown University and the President's at Eureka College do seem contradictory in tone. It is disappointing, for instance, that the new strategy - or refined old one - does not incorporate the lessons many US administrations have learned in dealing with the Russians. The best way to help the forces of moderation in the Soviet Union is to base American policy on two well-tested principles: One, be firm with the Russians and show that you will do what is necessary if challenged. Two, show Kremlin leaders that there is something positive to be gained by pursuing reasonable policies abroad. The Clark directive seems to focus more on sticks than carrots.
In general there is a risk in talking publicly about trying to force change in the Soviet Union. If this is perceived in Moscow as a threat, it could feed xenophobia, leading to even more repression internally. This has happened many times in Russian history. The fact is, the present regime is vulnerable: with agriculture in poor shape, the economy stagnating, the succession problem looming, Soviet troops fighting a relentless war in Afghanistan, Poland still in turmoil, and the international communist movement in disarray. The Soviet empire in effect is already ''shrinking''- of its own dead weight. So why interfere with a natural process? From Mr. Reagan's point of view, detente may be a failure. But the argument can be made that it has been hardest on the Russians.
Whatever the politically motivated rhetoric of the moment, it can be hoped that the deeds of the Reagan administration will reflect the more balanced thinking that comes with experience in office. That alone will help dispel the confusion.