There is less than meets the eye to Israel's decision yesterday to curb defense contracts with South Africa. Politically, the policy shift by Israel, one of the few countries still on unabashedly good terms with South Africa, can only worry Pretoria. This is not so much for what the announcement implies about Israeli-South African ties as for what it says about the depth of the swerve in American public opinion against the government here.
The Israeli decision came only 10 days before an expected move by Washington - on which Israel depends for hundreds of millions of dollars in aid - to press for such a step.
According to reports from Jerusalem, Israel's 10-member ``inner Cabinet'' also decided generally to reduce links with South Africa and to set up a committee to begin a two-month investigation of possible further steps in that direction.
But in practical terms, the initial Israeli move is unlikely to have much effect.
For one thing, arms embargoes have a funny way of sprouting holes. Since November 1977, South Africa has been subject to a mandatory world arms embargo voted by the UN Security Council. Still, military hardware and arms technology have seeped through - and not only from Israel. There is big money for private businessmen in selling weapons and weapons secrets, anywhere, anytime.
There are other factors, say Israeli and local analysts here, likely to minimize any early effect from the Cabinet move in Jerusalem.
Responding to the 1977 Security Council action, South Africa has moved energetically to develop its domestic defense industry.
Under a state-controlled umbrella known as Armscor, the Armaments Corporation of South Africa, a network of specialized companies has achieved something very close to self-sufficiency for South Africa in the production of most types of hardware.
Although official figures are unavailable, neither Armscor nor the government has made much effort to hide the fact that South Africa has become a major arms exporter.
Though it is impossible to say whether South Africa has actually manufactured nuclear weaponry - a closely guarded national-security secret - Pretoria has possessed, at least since April 1981, the capability of producing weapons-grade uranium.
By now, South Africa theoretically could have manufactured a ``slowly expanding nuclear arsenal of perhaps 15 atomic weapons,'' according to the newest edition of ``Going Nuclear,'' Carnegie Endowment expert Leonard Spector's annual survey of the world nuclear balance.
In the conventional arena, the South Africans' latest achievement, unveiled last July, has been to upgrade its aging force of French-design Mirage IIIa fighter aircraft with state-of-the-art guidance systems and weaponry. The revamped craft, dubbed the Cheetah, is cited by officials as a sign of South Africa's success in shrugging off the 1977 arms sanctions.
Some of South Africa's black neighbor-states have been amassing upgraded arsenals of their own. Angola, for instance, is said to have received MIG-21 and MIG-23 fighters from Moscow. Still, in the near term, South Africa seems in no danger of forfeiting its huge edge in the regional balance of power.
Further Israeli steps could have more-serious effects. The most visible sign of Israeli-South African military links is the sight of compact Uzi submachine guns slung across the shoulders of South African soldiers. But the most important Israeli-South African link, say nongovernment analysts here, involves computer-age technology. Still, even if a curb on computer dealings and the exchange of military know-how were announced, few analysts expect that it would stem considerable nongovernment contacts in this area.
Some analysts, moreover, see the Israeli fanfare over banning future government defense deals with Pretoria as a move to deflect political pressure from the Americans. If successful in this, they reason, Israel might well inch away from any determined break with South Africa during the eight weeks that the Cabinet committee has to chart possible further moves. This interim might also see a gradual lessening in fallout from the recent sentencing of Jonathan Pollard, a United States citizen caught spying on the US for Israel.
The US State Department responds: Spokesman Charles Redman welcomed the move as a ``positive development.''
He declined to say whether the United States had any direct role in the Israeli decision, but did say the US had discussed the issue with the Israeli government ``on several occasions.''
The State Department spokesman also declined to comment on whether there has ever been any ``leakage'' to South Africa of US arms supplied to Israel. The US has supported the arms embargo that was imposed on South Africa by the UN in 1977.