THE WORLD'S credulity might have been strained by the claim of Uganda dictator Idi Amin that three highly placed opponents of his chaotic regime died in an automobile accident - it might have, that is, if it had not already been shredded beyond repair. The blood that had already accumulated on the hands of Amin and his henchmen was more than enough to force even the most generous and reasonable people to reverse the presumption of innocence that otherwise might prevail.

Even so, the mind still boggles at the spectacle of terror now unfolding in Uganda. Anglican ArchBishop Janani Luwum, not long before his death warned that Christians in his country were in "grave jeopardy" from Amin's vicious security forces. Amin is a Moslem. Since the death of the archbishop and two ministers of Amin's government in that implausible "accident," reports from East Africa are grim concerning the fate of Christians and educated members of the Uganda commuity. It now appears possible that these deaths were part of a growing campaign that could lead to massive murder of men, women and children in that country.

When you think of the prospect of massive religiously motivated carnage in Uganda, it is necessary to recognize that there is plenty of evidence that Idi Amin and mass murder tend to go together. A leading newspaper in neighboring Tanzania branded Amin "the brutal soldier from the upper Nile," and it said that "thousands of innocent Ugandans have been found floating in the River Nile in what Adi Amin calls "accidents." By several reliable estimates, as many as 250,000 Ugandan citizens have lost their lives since Amin overthrew the regime of Milton Obote in 1971.

Now, Canon Burgess Carr, head of the All-Africa Conference of Churches, say he is "alarmed and terrified by indications that the murder of the archbishop may be part of a campaign of terror unleashed against Christians in Uganda." It is for these reasons that international humanitarian organizations around the world are urging that all the resources possible be applied to finding out what is going on inside Uganda and making certain the outside world gets the word.

What is the cure for a mad and murderous dicator? He has cripped his opposition through his terror tactics, and he has one of the strongest military operations of any East African country. Perhaps the only anction in the rest of the world has, beyond doing its best to get the facts, is universal condemnation of Idi Amin as the brutal murderer that he is being proved to be. In case he is under any illusions that he is respected for his extermination activites, he shouldd know that the civilized world looks on in Horror at him, and with sympathy for his victims. He should be made to know this - to the extent that he is sufficiently sane to recognize it. Any potential opposition figures, who might someday find the resources and summon up the courage to move against him, should also know it - for whatever heart it may give them. And finally, for whatever comfort it may bring them, so should the innocent and helpess citizens of Uganda who have the misfortune of living under his brutal tyranny.