FROM IMPORTANT domestic quarters and from the Soviet Union, the president's foreign policy drew interestingly consistent challenges over the weekend. Indeed, there was enough symmetry to make you think that, collectively if not yet individually, people are beginning to get the point of what Mr. Carter is trying to do. He is trying, we think, to convey a very simple message: If the Soviet Union wishes to combine a restrained competition with the pursuit of certain common objectives, then the United States is eager to cooperate in that enterprise, but Moscow cannot expect to run roughshod over American interests in some parts of the world without putting at risk its overall relationship with the United States. That was the gist of his Annapolis speech last week.

Senior members of the House International Relations Committee on the one hand and the AFL-CIO on the other now find the Carter policy uncertain. The congressmen find an uncertain commitment to detente, the labor people an uncertain commitment to standing up to Soviet power. We hope they study each other's positions, and try to empathize with each other's anxieties. For their concerns are not mutually exclusive. They are talking of the same policy - from opposite points of view. The policy lends itself to contrary interpretations because the reality it confronts is itself contrary. There are in Soviet policy and in the international situation elements both promising and disturbing. It is promising, in particular, that the Russians are at least exploring in SALT ways to restrain the arms competition, including their own buildup. The disturbing element is, in particular, the historically unprecedent deployment of Soviet military power in Africa. The United States cannot fail to react to both, and so its own policy is ambivalent, too.

It would be easier for policymakers, and easier on all our nerves, if reality were one-dimensional, as it is, for instance, in a war - or in an isolationist turning away from all responsibility for what goes on in the world. But reality, in fact, is ambiguous, uncertain and confusing, and much of the current foreign-policy debate fails to take this elemental fact into account. The country is not in a great budding crisis of international policy. It is in confusing circumstances, and will be for years.

Oddly enough, Pravda, in its reaction to Mr. Carter's Annapolis speech, seemed more aware than many American listeners of the ambivalence built into American policy. The speech, Pravda said, had "some positive moments," in its references to the importance of detente and arms control, and some "cold war" passages, in its references to internal Soviet affairs and Soviet support for "national liberation movements." Like some of the adminstration's domestic critics, who by now ought to know better, the Kremlin chose to attribute the parts it didn't like to the mechinations of Zbigniew Brzezinski and other dark precincts - this despite the fact that the speech was written out longhand and in solitude by the president himself.

More important than Moscow's unsurprising and rather defense-sounding complaints, however, is its recognition that there are different elements in American policy. From there, optimists are entitled to hope, Moscow can perhaps accept that there are also different elements in its own. Such mutual recognition, we think, is an essential prelude to removing the static currently in the Soviet-American air. The task for both great powers is to live with uncertainty, reducing as they can its risks and costs but understanding that no end to uncertainty is in sight.