THE FRONT PAGE of this newspaper yesterday posed graphically the leading question of American foreign policy. Two stories detailed trouble, one reporting a communist-backed drive into Eritrea, the other telling of American plans to rescue nationals threatened by a second communist-backed drive into Zaire. In a third story, a former director warned that the CIA's capacity to do necessary work for national security was being whittled away. Finally, president Carter himself was reported expressing frustration at the inhibitions Vietnam-minded Congresses had put on the executive's ability to aid friendly governments under communist siege.

Has the United States overreacted to the Vietnam trauma, leaving itself without the military and political resources - including executive authority and that elusive quality known as "will" - to deter aggressors and bolster friends? An ever-larger segment of the political community, we not, seems to think that is the case. The mood may not be one of panic, but the alarm is real.

Some part of the problem is the sense that the curve of Soviet-encouraged violence and power is rising at at a moment when the United States has neither recovered from the wounds of Watergate and Vietnam nor come to terms with changes in the international economy and the international balance of power. It is becoming an uphill battle to argue that the United States, having come through one good patch internationally (India, Spain and Portugal, Egypt and Sudan, etc.), is now simply passing through a bad patch. In any event, the outrage that fueled earlier demands to trim back executive power is yielding to the anxious feeling that the president, as the single responsible authority capable of direct action, cannot be deprived of the necessary tools. Paradoxically, that is happening even as misgivings spread about President Carter. He was elected, after all, to deal with a very different imperative: that of strengthening the moral and institutional structure of government's domestic initiatives, not of arresting the erosion of our influence and power overseas.

We do not offer this necessarily impressionistic view because we accept the validity of every element in it, but rather because we think it is taking on a force of its own that the president cannot ignore. How should he deal with it? We offer two general answers.

First, he should not be swept up in hasty improvisations whose immediate effect may be to still political doubts, but whose longer-term consequences may be harmful to American institutions or American interests or both. It would be foolish, for instance, to plunge into Zaire - though a sure and prompt response to Zaire's request for aid might be very useful. It would be even more foolish, to take another case, to relieve CIA of the burden of a legislated charter, as some of its more alarmist friends desire. What is required is a sound, un-ideological, case-by-case approach to each national security issue as it arises.

At the same time, the president must start demonstrating that he understands how different elements of his policy relate to each other. That has been a singular failure of his governing style. He does not seem to grasp that if you add up a push for human rights and a drive for non-proliferation and an effort to bring about peaceful accommodation in this region or that and a campaign for reducing arms sales and an outreach for detente - each good in its own terms - you end up with policy that is its confusion of means and purposes would be laughable if the effects of it were not so grim. In this, Mr. Carter seems lack discipline. He gives the impression of being so earnest about particulars as to not be serious about the whole.

It is not time to quake for the republic. The United States has elements of great material and moral power on which it can draw. But the president is not getting the best out of the many able people in his national-security apparatus. He is not projecting to the country a sense of purposeful participation in its own destiny. If Mr. Carter projected such a sense, we believe, he would tap support he does not seem to know exists.