FEW AMERICAN acts since World War II are so repellent as the protection extended to certain Nazi war criminals. To save their skins, this group ran to the American authorities at the end of the war and volunteered their services in what they correctly perceived was the coming contest with the Soviet Union. That they were harbored by the United States constitutes a continuing political and moral scandal.

Most of these criminals were wanted by the Soviet-bloc countries they offered to work against; other considerations aside, their situation has always been complicated by the fact that justice as the West knows it is not available where Soviet power holds sway. Very different, however, are the cases in which the harbored Nazis had committed war crimes against the United States' own allies, where justice American-style is available. The Americans had a deep obligation to honor the allies' claims to try people who had savaged their citizens. Nazis whose crimes had been committed in, say, France could not very plausibly argue that they knew something of value about the Soviet Union.

This is the context in which Americans have their own reason to contemplate the case of Klaus Barbie, the 69-year-old former Gestapo chief in wartime Lyon who was recently extradited from Bolivia to France. This notorious figure is accused of responsibility in the death of 4,000 French Resistance fighters and Jews and in the dispatch of some 7,500 other Frenchmen to death camps. It seems evident that but for the protection he received from Americans, he might have been tried long ago.

With the war over, Klaus Barbie came into the hands of the American occupation in Germany and moved into a house requisitioned by the Americans. Repeatedly the French asked the Americans to locate him and, when his whereabouts were established, to hand him over. The requests were turned away. On one occasion it was explained that he was needed for the "United States' national defense." On another, an American intelligence officer "played dumb" on grounds that, as the officer recently told a reporter, "orders are orders."

Some sense of how this criminal played his cards with the Americans can be gleaned from the report that in 1946 he wangled a particular introduction in order to obtain information on Romania for his work in the U.S. secret service. In 1950, local German authorities came looking for him, in vain, in connection with a jewel robbery in which the loot was recovered . . . by American investigators. Under an American travel document made out to a false name, he fled to Bolivia in 1951.

Yes, it was another time. Yes, it is easy to second- guess. But protecting Klaus Barbie was an ugly deception that cannot be repeated or condoned.