On paper, the West seems powerless to stop the Cuban and Soviet-backed offensive that Ethiopia is expected to mount against its secessionist province of Eritrea perhaps as soon as the next two or three weeks.

But Western analysts are not as concerned as might be expected considering their nearly universal belief that the coming Communist-led military onslaught will eventually succeed.

"There's trouble enough in Ethiopia to keep the Soviets busy for the next hundred years," one veteran Africa expert said.

Conventional military thinking suggests that the strike force now being switched from the Ogaden - perhaps 60,000 Ethiopians and 7,000 Cubans plus warplanes and hundreds of tanks - will sweep north through the western lowlands to seal off the Eritreans from their rear bases in Sudan.

The fighting is expected to be long and arduous. It will probably take at least a year to "pacify" Eritrea and then only to a low level of periodic violence.

But the relative Western equanimity about Ethiopia is based on the belief that it simply is not a good place to be involved, either now or after a major Ethiopian victory.

Analysts see the turmoil in Ethiopia as one of the cyclical upheavals which have marked the ebb and flow of the Ethiopian empire for more than a thousand years, and they do not hold fears that Ethiopia will serve as a center of ideological conlagion for the region.

Such Cold War thinking was inititally prominent in the years immediately following 1960, when a large number of African nations achieved independence.

First there was the Soviet scare, then a Chinese version which was supposed to run across the thin waist of the continent from the Indian Ocean to the Atlantic.

The record indicates however, that Africans have shown a remarkable resistence to Marxist ideology - especially in such countries as Guinea or Congo, which have formally embraced Marx's scientific socialism.

Thus some analysts question the applicability of an African "domino theory" and the inevitability of Soviet influence being extended across the Red Sea from Eritrea to the oil riches of Saudi Arabia.

Modern technology has made obsolete the American communications base at Kagnew in Eritrea - the main reason the United States countenanced Ethiopian annexation of the province in defiance of U.N. resolutions and backed the emperor.

As one analyst bluntly noted, Ethiopia has no known oil or any other minerals in sufficient quantities worth hanging onto and there is therefore little reason for the west to be concerned about its fate.