Nearly everyone agrees that apartheid is repugnant. But pushing South Africa to end its system of forced racial separation presents the United States with the wrenching task of balancing moral and strategic interests that appear to conflict.
South Africa is the main supplier of several minerals considered essential to US economic and military security. In addition, it controls the shipping lanes around the Cape of Good Hope, which carry 70 percent of Europe's oil supplies from the Persian Gulf.
South Africa also plays a dominant role in the economies of a dozen states in southern Africa, experts say. Its role as a primary source of food, transportation, and technical support makes South Africa crucial to the economic and political stability of the entire region.
For the moment, the moral question dominates the political debate.
Congress is now pushing harder at South Africa, reinforced by continuing racial violence there. The House voted 380-to-48 Thursday in favor of a House-Senate compromise bill that would:
Ban imports of South African gold coins, called Krugerrands.
Prohibit bank loans to Pretoria.
Prohibit the sale of computer and nuclear technology to the South African government.
The compromise bill also calls for an end to new private investment in South Africa in one year if South Africa fails to make progress toward ending apartheid.
Officially, the White House opposes sanctions, and it sharply criticized the compromise bill Thursday.
But recent events in South Africa may have put President Reagan under considerable pressure to sign the legislation. In both the House and the Senate, anti-apartheid bills have passed by large enough majorities to override a presidential veto.
For years, US policymakers have struggled to reconcile opposition to apartheid with the practical needs for strategic minerals and stability in southern Africa.
Supporters of the Reagan administration's policy of ``constructive engagement'' say stiff economic sanctions and any future disinvestment would certainly hurt US companies in the region, most of which adhere to fair employment practices.
But worse, such actions would risk weakening South Africa's economy, they say. Since blacks would be the first to suffer, increased political polarization and, eventually, greater regional instability could result, they add. Economic sanctions could also provoke South Africa to retaliate by cutting off strategic minerals to the US.
Opponents of constructive engagement agree that South Africa is strategically important. But they contend that the way to maintain US strategic interests in the long run is to put US policy on the side of history, even at risk of retaliation in the short run. The way to do that, they say, is to adopt a more punitive policy that forces South Africa to take immediate steps to dismantle apartheid.
The most critical strategic issue is access to minerals, which are needed to meet the growing US demand for specialty steels and alloys used to make high-technology products, including military hardware.
The US relies on South Africa for many precious metals, including 55 percent of all chromium imports, 70 percent of manganese imports, and over 80 percent of imports of platinum-group metals, used in electrical contacts on modern missiles.
In addition, the US indirectly relies on South Africa for imports from other nations in the region, which depend on South African rail lines and port facilities. For example, cobalt from as far away as Zambia and Zaire passes through South African ports on the way to the US. Over 50 percent of US imports of cobalt, used in computers, comes from the two countries.
The US has taken steps to diminish reliance on such imports, either by finding substitute materials or alternative sources, say strategic-minerals experts. Even so, the problem of dependence, spurred by the current US military buildup, has become worse. And US strategic reserves of many essential minerals are comparatively low.
Under these circumstances, the loss of such minerals due to political instability in South Africa could result in widespread economic dislocation in the US, forcing prices up and employment down and compromising US security interests.
``There's a risk of the kind of economic chaos created by the OPEC [Organization of Oil Exporting Countries] oil embargo,'' says James T. Bennett, professor of economics at George Mason University and co-author of a recent Heritage Foundation study on strategic minerals. ``If you lost the minerals, it would take years to develop alternatives -- and we need them now,'' he says.
Professor Bennett notes that the only other big supplier of minerals like chromite, used in the jet engines of high-performance military aircraft, is the Soviet Union. ``There's no reason to believe that, if South African supplies were disrupted, the USSR would come to the aid of the US,'' Bennett says.
Statements made Monday by South African President Pieter W. Botha illustrate the risks of pushing too hard for reforms, say opponents of strong sanctions.
Reacting to possible UN-sponsored sanctions, President Botha threatened to expel 1.5 million foreign black workers whose earnings are a key source of foreign exchange for several neighboring countries. Botha also threatened to sever transportation and communications links with the region.
Experts say such action, if carried out, could cripple the region economically, threatening political instability and jeopardizing US access to needed minerals.
But supporters of strong sanctions say that by not identifying with the interests of the black majority in South Africa now, the US risks being cut off entirely when political change finally does come.
``When white rule is finally doomed, we don't want to go down as the one government that held the coattails of the remaining vestiges of colonialism and racism in Africa,'' says Rep. Jim Leach (R) of Iowa, one of the original supporters of anti-apartheid legislation in the House. ``The strategic argument is thus for an immediate shift of US policy away from anything that appears to legitimize the government in power.''
``Sanctions could cause disruptions and costs,'' says Brian McCartin of the Center for Defense Information. ``But they're not so high that we should acquiesce to apartheid.''
Mr. McCartin says the US has weathered at least four major materials-supply interruptions since World War II. In each case, he says, a combination of conservation, diversification, and substitution enabled the US to adjust over time. McCartin also notes that strategic stockpiles are adequate to sustain at least a short-term interruption.