SLIM BUT PROMISING gains in food production have been made by many African countries, but Angola and Ethiopia are conspicuous exceptions. There famine on the immense scale of earlier years again looms. Marxist regimes rule in the two countries; they now seek food aid and in so doing pose hard policy choices to would-be donors, the United States first among them.

In Ethiopia, drought aggravating underdevelopment is the proximate cause of the threatened famine. But the condition is greatly worsened by the Mengistu government's farm collectivization and resettlement policies and by the cost of the assorted wars it conducts against its own restive citizens. Having followed the Soviet example in imposing its hand on the countryside, the regime now resists latter-day Soviet advice for farm reform.

As is usual when a Soviet Third World client gets into this sort of trouble, it turns to the international community for rescue. In similar circumstances only three years ago, the American government and public performed prodigies of relief. It is infuriating, but may be necessary, to do it again. To make the government mend its ways, a group of congressmen led by Rep. Toby Roth (R-Wis.) and Rep. Bill Gray (D-Pa.) favor imposing certain limited economic sanctions -- supposedly targeted on the Ethiopian government, not on the people. But this is a gang that has never shrunk from exposing millions to starvation to keep itself in power. Sanctions or no, aid should be sent.

In Angola, the usual disabilities of underdevelopment have been compounded by a 12-year civil war that rages with special intensity in the country's breadbasket. Fighting and land mines have driven great numbers of peasants off the land, and the regime's policies have driven many of those who remain out of the market. The government chooses to expend very little of its available resources on its hungry citizens, preferring to leave their fate to the mercy of foreign donors. Moscow's billions in aid go to guns.

Politically, the United States is in an awkward place: it helps arm Angolan insurgents even as it provides relief that, by the nature of relief, helps the government. Still, it is already the principal provider of humanitarian food aid to Angolans, and it should do more.