Dual message

In case anyone was likely to miss the point, the Reagan administration amply sought to set the tone, in briefings for reporters, for the President's speech yesterday and Secretary of State George Shultz's trip to Stockholm to meet with Soviet Foreign Minister Andrei A. Gromyko.

The headlines: ''Reagan to ask Moscow to help end arms race''. . .''White House set for election-year effort at improving US-Soviet Relationship''. . .''Shultz vows 'constructive spirit' in Stockholm talk.''

But there was another series of weekend headlines sending other messages: ''Reagan is said to find breaches by Soviet of agreements on arms''. . .''US and Britain bar concessions to Moscow on arms.''

What's up? Why the lurchings in administration posture from hard-line ''You can't trust the Kremlin'' to moderate ''Let's talk''?

Obviously Mr. Reagan has different audiences. His Monday morning speech was timed for Europe's evening telecasts, and except for Mrs. Thatcher - for whose company the White House seems to reserve its best hard-line signals - the constituency there longs for some breakthrough in the arms-talk impasse. In the media, Mr. Reagan can also count on a constituency favoring moderation in his foreign-policy rhetoric. He played to this astutely in setting up his 1982 trip to Europe, which he proceeded to contradict with confrontational tactics in Versailles and an ideologically bristling speech at the House of Commons.

Reports of moderation in presidential demeanor are usually accompanied by stories attesting to the ''ascendency'' of the secretary of state. Former Secretary of State Alexander Haig's much-reported ascendancy prior to Versailles looked silly against his sudden plunge from power right after.

On the hard-line side, Mr. Reagan has another constituency - the conservatives in both parties who believe US-Soviet agreements have been based on one-sided concessions on the West's part, undermining US security. To satisfy this group, the President preempted his own more moderate speech Monday by acknowledging ''violations or probably violations'' of some terms of several arms control agreements the Friday before.

And so it goes. The Democrats press Mr. Reagan hard on the theme, ''Are you safer today than you were four years ago?'' Again, presidential rhetorical moderation helps - as long as it's offset by affirmations that peace must be guaranteed by strength.

Frankly, Mr. Reagan's speech, for all its advanced billing, contained a dual message. ''Strength and dialogue go hand in hand,'' Mr. Reagan said.

The dual theme sets the stage for Mr. Reagan's re-election campaign. He will take credit for establishing, his first term, a strong arms bargaining position that could lead to a more productive US-Soviet dialogue in a second Reagan term. Politically, his administration feels it only has to show a willingness to talk, not results in the form of an agreement, in 1984.

''We have halted America's decline,'' Reagan said, linking US economic strength to its military security. ''America's deterrence is more credible and it is making the world a safer place.''

But is it? Mr. Reagan's equating of safety and deterrence will be challenged.

George F. Kennan, the Kremlin analyst, sees 1984 Soviet-American relations more darkly. ''All arms control talks, nuclear and conventional, have broken down,'' he notes. ''The weapons race is now in many respects effectively out of control. Soviet-American trade has declined to almost insignificant levels. . . . Official communication between the two governments has sunk to the most rudimentary level imaginable for nations not officially at war.'' The two superpowers will not be ready to resume even some provisional working relationship without ''restraint in polemical rhetoric.''

To our ears, there was no backing away by Mr. Reagan from his fundamental ''peace through strength'' position in his speech this week. He apparently will wait the Soviets out, through 1984 if necessary, just as it appears the Soviets will wait him out, to see whether he survives the election.

Reagan was telling critics he is alert to their complaints while assuring supporters he is giving no ground.

In this he signaled consistency, not a new turn from deep-chill US-Soviet relations.