AFTER A JERKY start, the administration is getting its human rights act together. At his last press conference, for instance, President Carter criticized Uganda, South Korea and Cuba, showing that his concern was not limited to the Soviet bloc. He hasn't turned his back on Soviet violations, and shouldn't, and can't. But he could not have maintained his early heavy focus on Russia without risking the spoiling of the Soviet taste for the strategic arms talks, and much else. Though no one can say precisely how much rights traffic the overall East-West road will bear, the question must be kept continually in mind. By demonstrating a worldwide concern for rights, moreover, Mr. Carter equips himself to tell the Russians, as they protest, that he cannot make an exception for them.

For the long haul, the burden of the policy must be shifted from the President, who by now has amply established his personal commitment, to the bureaucracy. The President has got to have that flexibility. This is not simple: just about every Russian dissident and Jewish "refusenik" is petitioning Mr. Carter directly. Given the lingering political repercussions of the campaign debate over Mr. Ford's refusal to receive Alexander Solzhenitsyn, Mr. Carter could hardly have avoided answering Andrei Sakharov's letter himself. But in his letter he said he'd help others through his "good offices" - through diplomatic channels, that is - rather than through the postal service, and that, in our view, is how he should proceed. That, after all, is what diplomatic channels are for.

Mr. Carter, at his news conference, evaded a question on whether he would cut aid and arms to countries that engage in political repression. He took the easier route of noting that, since his election, a dozen dependent countries had demonstrated a bit more sensitivity about human rights on their own. That is, of course, a one-shot effect. A day later, however, Secretary of State Cyrus Vance addressed head-on the question his boss had dodged. In a major departure, he recommended cutting military aid to Argentina and Uruguay, countries facing no military threats, and to Ethiopia, which is on a war footing. The recommended cuts were small. Their echo is sure to be heard around the world. Mr. Vance passed over South Korea, which represents the hardest case: a gross violator of human rights, but also a country heavily dependent on American military support and one in which Washington has a large security interest. But it's probably wise to proceed by degrees.

The President notably strengthened the American bargaining position by scoring the United States' own visa and internal-travel restrictions placed on foreign Communists. As we have recently remarked ourselves, these embarrassing anomalies should be removed.Removal would highlight American seriousness toward the Helsinki agreement, which happens to be a major human rights lever now available for use on Moscow. By itself respecting Helsinki, the United States can better urge others to respect it. Diplomacy, as always, begins at home.

We feel compelled, nonetheless, to add a caution. Mr. Carter is embarked on a burst of national self-righteousness of a sort quite familiar from the American past. It involves the acceptance, as a legitimate goal of foreign policy, of the promotion of American values in many different countries where they are rooted shallowly or hardly at all. This effort is exciting, to some even ennobling; it sounds fine while it unfolds, or, more precisely, before it has had time either to succeed or to fail. But it is pregnant with pitfalls and frustrations. Allowed to get out of hand, it can produce a ruinous arrogance. It is something to applaud - and to approach with great care.