Two small steps ... giant leaps for mankind? Soviets and US make historic policy shifts

The Soviet Union in essence signed the liquidation papers this week on its 15-year investment in southern Africa. Though not a formal signatory to the historic accord on Angola and Namibia, Moscow committed itself to send home the 50,000 Cuban troops it has been supporting in Angola. This follows the beginning of the withdrawal of Soviet troops from Afghanistan, reduction of troops along the Chinese frontier and in Mongolia, and the beginning of withdrawal of Vietnamese troops from Cambodia. It is part of a pattern of contraction of the Soviet outer empire. Moscow is still giving aid to the Sandinista regime in Nicaragua, but on a reduced scale.

Also noteworthy this week was the success of the PLO's Yasser Arafat in using the key words that have untied the hands of American diplomacy and allowed the United States to speak directly to and with the PLO. This signals immediate progress toward a new peace initiative for the Middle East.

The liquidation of the Soviet venture in southern Africa will take time. The first step begins April 1, 1989, when Cuban troops are to pull back from southern Angola while South African troops begin to withdraw from northern Namibia.

The plan requires the Cubans to send 3,000 of their troops home by April 1, when Namibia's transition to independence is set to begin. (The former German colony has been ruled by South Africa for 73 years - most recently in defiance of the United Nations.) The Cubans are also required to redeploy all of their remaining troops north of the 15th parallel by August. By November they should have sent 25,000, or half of their present total, home. The final withdrawal of the last 12,000 should take place by July 1991.

South Africa, which has been maintaining an estimated force of 50,000 troops in northern Namibia, is required to reduce its strength there to 1,500 during the first three months of the transition period beginning in April. The 1,500 will be restricted to bases south of the Angolan border in Namibia. Eventually all South African troops are to leave an independent Namibia.

The transport of Cuban troops to Angola in 1974 was a surprise achievement of Soviet military logistics. Washington woke up one morning to discover that they were there, in substantial force. Moscow provided the air lift, the arms and equipment, and the pay packet. It caused deep anxiety in Washington, which responded ultimately with aid to an insurgent force under Jonas Savimbi, but the Soviets got there first.

The South Africans also backed Savimbi and eventually deployed a force of similar strength to the Cubans. Recent, large-scale battles between Cubans and South Africans proved costly to South Africa, which is also under heavy pressure from black dissension at home. Peacemakers for the Middle East had a bumpy road in arriving at US recognition of the PLO. A high-level delegation of American Jewish leaders met a PLO delegation in Stockholm two weeks ago, under the aegis of the Swedish foreign office. At the Stockholm meeting Mr. Arafat is said to have repeatedly said he recognizes ``the right of Israeli to exist.''

But when it came to his public speech at the special session of the United Nations General Assembly in Geneva this week, he did not specifically use the code phrase ``Israel's right to exist.''

This dates back to the days of Henry Kissinger, who promised that the US would not deal with the PLO until it does recognize ``Israel's right to exist.''

A few hours after Arafat's Gevena speech, after hearing from Washington, the PLO chairman did use those magic words. The same day, the United States announced an end to its 13-year boycott of the PLO.

In effect, US diplomacy helped this week to hasten for Israel the time when, at a big international conference, it would face a rising demand for it to recognize the right of the Palestinians to exist.

So far the question has always been whether the Arabs would accept the existence of an Israel. This has now been turned around into a question whether Israel will accept the existence of the Arabs.