Switching national security advisers would weaken US hand

THE pressure from rightist ideologues is mounting to appoint Jeane Kirkpatrick national security adviser. This is a remarkably bad idea regardless of the foreign policy strategy that Ronald Reagan wants to pursue.

And he is on the record as having assured the electorate that during his second term he would seek to improve the United States-Soviet Union relationship - something that his United Nations ambassador has made a career of opposing.

The President is a man of broad strategic vision who is not known for attention to detail. Accordingly, the composition of his team is of particular importance. At this point, there are two somewhat loose coalitions competing for Mr. Reagan's soul. One consists of tough-minded pragmatists and includes Secretary of State George Shulz, National Security Adviser Robert McFarlane, Commerce Secretary Malcolm Baldrige, and White House Chief of Staff James Baker. Not one of them is a detentist. None harbor illusions regarding the Kremlin's policies and intentions. None advocate unilateral concessions for the purpose of cajoling Moscow into civilized behavior.

But they and particularly their exceptionally competent and able lieutenants - Richard Burt at State, Lionel Olmer at Commerce, Richard Darman in the White House, and Jack Matlock on the National Security Council staff - know that the Soviet regime is not about to collapse and there is no alternative to dealing with it. Disregarding diplomacy would not only make the superpower rivalry needlessly emotional and explosive, it also would create a risk of alienating America's allies and polarizing domestic opinion. Only the Soviet Politburo would benefit from that.

On the other side are Defense Secretary Caspar Weinberger, CIA Director William Casey, and Mrs. Kirkpatrick. Their attitude toward Communist Russia is openly confrontational. Negotiations with the ''focus of evil'' are feared on grounds the Soviets would participate only to lull the West into a false sense of security. Cooperation with the USSR in that view represents a deplorable appeasement.

Where does Mr. Reagan stand? During his first term he refused to choose between the two sides. There was enough peaceful rhetoric and negotiating flexibility to keep the allies and the American public in line. But not enough was offered to the Politburo to encourage any accommodation. Diplomatic accomplishments were absent, but so were disasters.

Meanwhile, US power and self-confidence were being rebuilt. The Soviet Union was going through a period of external and domestic troubles. The administration could make a credible case that the situation in the US-Soviet relationship was not all that bad.

Replace Mr. McFarlane with Mrs. Kirkpatrick and chances are that ideology will prevail over pragmatism, zeal over prudence, simplistic cliches over an appreciation of complexity. Forget then about the second term becoming a period of opportunity to achieve some modus vivendi with Moscow.

The United States national security formulation process, if dominated by anti-Soviet purists, will preclude the development of negotiable arms control positions. The Kremlin will be bound to interpret the appointment as evidence that nothing can be accomplished with Mr. Reagan. That would discourage the Soviets from bargaining in good faith.

Some of the President's supporters would only be pleased if nothing comes out of talking to Konstantin Chernenko and his associates. And a case can be made that the nation can survive without a trivial pursuit of marginal limits on two huge nuclear arsenals. The trouble is that - notwithstanding the Soviets' angry response - there is also likely to be a backlash in Western Europe and in the United States itself.

The West Europeans by and large have welcomed Reagan's reelection, but they are not comforted by a rise in superpower tension. Credible negotiating strategy toward the Kremlin is a prerequisite for the alliance management. The right wing has contempt for the West European preoccupation with talking to the Russians.

But that is beyond the point. NATO is a coalition of democratic societies with their own interests, traditions and policy styles. To ignore them would be to invite a painful family dispute undermining Western cohesion vis-a-vis the Soviet Union. That much we should have learned from the fiasco over efforts to twist European arms in the dispute over the Siberian natural gas pipeline.

Domestically, Mr. Reagan has to confront the reality of dealing with Congress , where his supporters are still in a minority in the House and have lost seats in the Senate. Congressional Democrats and their moderate Republican allies made it abundantly clear that the administration is not going to be allowed free rein in foreign policy. In the past a compromise orchestrated by the moderates in both the executive and legislative branches saved the President from several painful setbacks on the Hill. The next session of Congress will have to determine the fate of further appropriations for the MX missile and aid to Contras in Nicaragua. Even those who question both programs should (at a minimum) be reluctant to let them die outside the framework of diplomatic negotiations. Yet even in the conservative camp, many fear that Ambassador Kirkpatrick, an unabashed skeptic of arms control and equally unabashed apologist of right-wing authoritarians, would have much credibility in building congressional support.

At the Republican National Convention Ambassador Kirkpatrick delivered a speech extreme in its partisanship. She went so far as to charge that those who disagree with the administration's policies ''blame America first.'' She went beyond attacking the judgment of critics of the President. There was a clear-cut implication that there is something wrong with their patriotism as well. Polemics of this sort made her a hero to some. But among all distinguished hard-line public servants available to the President, is she the best qualified to act as a shaper of the bipartisan foreign policy?