AS FAR AND AWAY the largest and most powerful African country and--here is the special American interest--as a democracy, Nigeria is a standing reproof to the notion that Third World countries cannot handle the demands of a modern "Western" political system. Actually, though Nigeria is not hesitant to acknowledge its borrowings from its former British colonial masters and from the American democratic model, its commitment arises from its own traditions and from its acknowledged need for a system allowing the development of a society of great ethnic and regional diversity. Nigerians do not believe they have imported a foreign system. They believe they are governing themselves their own way.

Today Nigeria takes its next major step when it conducts the first presidential elections to be held under civilian auspices since the armed forces surrendered power after 13 years and sponsored elections in 1979. This time it will be up to the 90,000 police, not the army, to keep any local disorders within bounds. In the country there is evident a full sense of the importance of the occasion. The 1979 poll was an immensely significant nation-building event, but Nigerian politics still has a strong ethnic and regional content. It was barely 15 years ago that the attempted Biafran secession produced a calamitous civil war. In a continent where military dictatorship and one-party rule remain the dominant political modes, Nigeria's intent to deepen its democracy is vastly encouraging.

The country's return to democracy in 1979 owed something to the availability of large oil revenues, a useful solvent for all manner of social frictions. The subsequent fall in world oil prices cut Nigerian oil earnings from $26 billion to $10 billion and caused painful cutbacks in development projects and in the level of popular services. It fell to President Shehu Shagari, who is running for reelection now against five challengers, to manage this immensely difficult contraction on top of the other tasks involved in governing an immense, diverse and demanding nation like Nigeria.

Nigeria may not have the high visibility in Washington that it enjoyed during the administration of Jimmy Carter, who made Lagos central to his whole African policy. There is, nonetheless, no lack of American interest and good will in seeing how Nigeria fares now.