OF ALL THE reasons why it is difficult to deliver enough food fast to the starving millions in Ethiopia none is more perverse than the politics of the country's several civil wars. There are instances in which rebels in Eritrea and Tigre provinces are at fault -- for example, in seizing the major relief center of Korem. The deeper fault, however, lies with the government of Lt. Gen. Mengistu Haile Mariam, which is still allowing political considerations to get in the way of efforts to move supplies through.

True, Gen. Mengistu has come a distance. He has listened to the United States, the leading foreign government in the relief effort, and to the private international relief agencies that deliver most of the food. He has become more impartial in the life-or-death matter of allowing food to be moved to rebel-held areas, although he has not opened up his country to make it easy for Ethiopians to benefit from all the food now flowing in. Even if Ethiopia were not in a state of war, its disorganization and poverty would make the provision of relief an exacting exercise.

What is unforgivable, however, is that Gen. Mengistu refuses to do the one thing he could do to make a great improvement. The rebel groups have called for a truce or negotiation to facilitate distribution of relief. But he appears to believe the "bandits" would use a truce simply to strengthen themselves and to gain de facto recognition. It is possible that some of his advisers are telling him that the guerrillas' appeal indicates a degree of weakness and that this is the moment for the kill.

What Gen. Mengistu fails to acknowledge is that the people starving in rebel-controlled areas are Ethiopians, ostensibly his people. What moral claim does he have to be their ruler if he denies them lifesaving food? The first national priority should be feeding the people. That would be the humane policy. A "food truce" should be organized, generally or locally, to put relief operations entirely off limits to military operations by all the parties. As the leader of his country, the general is the logical person to make this idea his own, either by setting an example or by talking with the rebels.

Donors have a right and a duty to demand that the Ethiopian government move this way. The Soviet Union, which is otherwise doing far less than its role as Ethiopia's patron dictates, should be expected to press for a similar policy. It is the only way to make sure that the available aid will go as far as possible. Some close observers think a food truce might lead to a political truce. If it happened, fine; if it didn't, much good would have been done.