Kissinger's back in a saddle, but will he be a white knight?

The telephone call for which Henry Kissinger has been waiting for 21/2 years finally came this week. It was the White House saying, in effect: ''Henry, we are in trouble, come and save us.''

The White House was in trouble on several foreign affairs matters, but most immediately over Central America. In the long run the Middle East is by a wide margin more dangerous. But as of this past week President Reagan was committed to a Central American policy which the Congress was on the verge of repudiating.

There was a movement in Congress to forbid more funds for carrying on a supposedly ''covert'' military offensive from Honduran bases against the government of Nicaragua.

Congress did exactly that (voting to forbid covert aid) in 1976 when Henry Kissinger was secretary of state and the issue was Angola. A Marxist faction there was winning out with Soviet support and Cuban troops. Dr. Kissinger was using the CIA covertly to contest the outcome. Congress stopped him.

For Mr. Reagan this situation is worse because it is closer to home. He has been backing the right-wing regime in El Salvador for two years. The military offensive from Honduras against the Marxist-led regime in Nicaragua had been long planned, troops had been trained and armed and deployed, and the advance into Nicaragua was actually under way.

In the administration view, to call off the offensive now would collapse the campaign against Nicaragua, spread consternation among rightist factions all through Central America, and probably mean victory for the leftist insurgents in El Salvador. In such circumstances Mr. Reagan would be presiding over a fiasco comparable to the Bay of Pigs affair of unhappy memory for Washington.

The political situation in Washington is such that Mr. Reagan had to do something quickly. Calling in the redoubtable Henry Kissinger with his reputation as the wonderworker of diplomacy is clearly intended to head off such a fiasco in Central America.

Congress is not likely to repudiate Mr. Reagan's Central American policies until it has first seen what Dr. Kissinger can conjure up. Mr. Reagan has gained time. Conceivably he may still save both the rightists in El Salvador and the counterrevolution in Nicaragua.

But that of course depends now on whether the Kissinger talent for crisis control has survived 21/2 years of waiting for the expected telephone call from a new Republican administration. It never came - until this past week.

For a supposedly indispensable man, 21/2 years is a long time to wait. It could erode even Dr. Kissinger's monumental self-confidence. We shall see.

Also, we do not yet know whether he will interpret his mandate as being to reconcile the opposition in the Congress to the military solution in Central America which President Reagan favors - or to find a path out of the military jungle toward a political and economic solution which many in Congress favor.

At the moment the situation is that a fiasco has been staved off and time gained for rethinking the Reagan approach to Central America.

Of course, if Dr. Kissinger uses this opportunity, with the brilliance that has been credited to him by admirers in the past, there will be opportunities for more service to his third President. The arrival in Washington during the past week of President Amin Gemayel of Lebanon underlines the fact that American diplomacy in the Middle East is stalled in a dead-end street.

Israeli Prime Minister Menachem Begin recognized the situation by postponing his visit, which was to have followed the Gemayel visit. There is really nothing for Mr. Begin to discuss with Mr. Reagan right now.

Motion toward peace in the Middle East could be regained if Syria were willing to join Israel in withdrawing totally from all of Lebanon. But Syria has dug in its heels. And, while this lasts, Israel has gained American acceptance for remaining in southern Lebanon. Hence, Israel is preparing for a long-term occupation of much of southern Lebanon, including the two important and ancient port cities of Tyre and Sidon.

Conversely, Syria, backed by Moscow, refuses to consider mutual withdrawal if Israel retains the sort of influence over southern Lebanon which was spelled out in the Lebanon-Israeli withdrawal agreement worked out under the auspices of US Secretary of State George Shultz.

This is the kind of deadlocked situation that Dr. Kissinger was accustomed to handle by ''shuttle diplomacy.'' There could be more work for him ahead - but only if he can first extricate Mr. Reagan from Central America.

And what would come after that?

Anyone who read William Safire's column in the New York Times July 17 knows the answer. Mr. Safire is a brilliantly articulate voice of that ''neoconservatism'' which opposes almost all traffic with the Soviets. Mr. Reagan is obviously headed down the road toward a summit with Moscow's Yuri Andropov. Mr. Safire gave fair notice that he will be resisting every step of the way.

The first step was taken the week before (July 15), when Mr. Reagan gave his approval to a compromise arrangement with the Soviets at Madrid on the wording of a text on human rights. In itself, the matter was minor - at least when compared to war and peace issues such as arms control. The question was whether the wording should be harder than the Soviets would accept. It was softer. They accepted.

Mr. Reagan said the agreement at Madrid could lead to ''a more stable and constructive relationship with the Soviet Union.'' Mr. Safire labeled the agreement ''a negotiating defeat'' for the US, which means that Mr. Reagan's political right will be firing at him from the side all the way from the minor agreement at Madrid to a possible meeting with Mr. Andropov.

It is intriguing to think of Dr. Kissinger planning Ronald Reagan's march to the summit with Mr. Safire again firing from the saddle at the circled wagons in one encounter after another. The idea must have crossed Dr. Kissinger's mind during the past week.

But long before that can happen we will have to see how the retread operation works in the Central American matter. Dr. Kissinger has acquired many critics during his career. Congressional liberals and conservatives distrust him equally.

Among liberals he is held responsible for the ''Christmas bombing'' of Hanoi and invasion of Cambodia (Kampuchea), the overthrow of Chilean President Salvador Allende Gossens and the coming into power of dictator Augusto Pinochet Ugarte. Among the conservatives he is held responsible for ''detente,'' a word that is anathema among all orthodox right-wing Republicans - and also among many conservative Democrats.

Dr. Kissinger's return could yet become one of Mr. Reagan's worst blunders. Dr. Kissinger is entitled to some satisfaction, however, over the fact that he has been recalled to service by those who 2 1/2 years ago thought they could get along without him.