Nigerian election campaign; DEMOCRACY WITH A TRIBAL BEAT

From the hilltop, hundreds of rusted tin roofs stretch across the parched landscape. A cloud of dust rising in the shimmering noon heat signals that a caravan is winding its way down the opposite hillside. It draws close and the caravan's assorted vehicles sway rhythmically through Ede's deeply potholed, dusty streets - Peugeots, Toyotas, and Datsuns crammed with smiling black faces shouting, ''One Nigeria, One Nation!'' as drums beat and villagers sing.

Shouting, thrusting their fingers skyward like college football fans, the caravan riders try to win support from the locals for a stronger federal government and for President Shehu Shagari's National Party of Nigeria (NPN). From the crackling loudspeaker atop the lead van comes the message, ''Our national President has instructed you not to pay the local flat-rate tax imposed by the Oyo State government.''

Several smiles and shouts of ''One Nigeria!'' from villagers show there is scattered support.

NPN's choice of Ede for this political rally represents a calculated gamble. The numerous hostile, stony faces glaring from the shop stalls and roadsides indicate this is a stronghold of the opposition - the Unity Party of Nigeria (UPN).

At issue is the degree of power that President Shagari and the NPN, which controls the federal government in Lagos, can exercise over the 19 state governments that compose the Federal Republic of Nigeria. NPN's rally in Ede shows the obstacles Shagari's drive for a strong federal government faces in a country whose political history has revolved around deep divisions between Nigeria's three major tribes - the Yoruba in the west, Hausa-Fulani in the north , and Ibo in the east.

Nigerians tend to identify with tribe and locality rather than the nation, and this was a major cause of the Nigerian civil war (1966-70) that led to military rule until 1979.

Since Shagari defeated Chief Obafe Awolowo in general elections in 1979, the country has maintained a vibrant multiparty political system modeled along US lines. In the Nigerian National Assembly, each of the 19 states and five political parties is represented in the Senate and House of Representatives. President Shagari and the NPN control seven state governments and hold a majority of seats in both houses. The UPN, under Awolowo, controls five states, among them Oyo State, which includes Ede.

Seeking to increase nationalistic identification among the major tribes, Shagari has pledged to use the country's oil wealth to increase food production and provide low-cost housing in each of the 19 states. At the same time, Awolowo and the more tribalistic UPN have concentrated on their promise to provide free medical care and education in the five states where they control the governments.

As in America, both sides make promises, then must decide after the election which ones can be kept. In Nigeria's case, promises of increased development rest on the presumption that the necessary funds will be generated by oil exports. The stark economic reality of the world oil glut has turned grandiose dreams into broken promises. Nigeria's crude oil exports have fallen from an expected 2 million barrels per day to about 600,000, and the resulting shortfall of funds has provided the ammunition for a lively political campaign. In gearing up their party machinery for the 1983 general election, the NPN has chosen Oyo State as a major focal point. A sound victory over the UPN there would signal a giant step in the party's efforts to ensure that Nigeria's development policies will be determined by a strong federal government rather than at the state level. As one NPN organizer explained, ''We are trying to kill the tribal aspects of our political life.''

The caravan halts, spilling its human cargo before the two-story adobe palace of the oba (paramount chief) of Ede. Though prohibited from active political campaigning by Nigeria's constitution, the oba sits at the head of the council that rules on matters of local importance. Without his blessing, the NPN will make little headway in Ede.

The incessant rhythm of the talking drums, brass bells, and cowrie shells colliding with hollow calabashes drifts through the palace windows and punctuates the effusive praise between NPN's state chairman and the oba. As they fall silent, a bustle of activity ushers in the oba's seal of approval - gifts of French champagne, cognac, and scotch. Beaming white smiles in the sea of black faces indicate this African political rally is off to a good start.

Hundreds of shuffling feet carry the throng of men through the narrow streets toward the town mosque. The women watch solemnly from a distance. Navy- and gray-clad Nigerian policemen, glancing uneasily at one another from under the rims of their oversize helmets, cluster at the palace entrance. The explosion of three black-powder rifles rips the air. But the gunshots are part of the celebration, not an armed attack by the opposition. The crowd surges forward, surrounding the NPN van and filling the dusty square.

NPN organizers find cause to smile over the turnout of some 200 voting-age males. The traditional tribal scars etched in their faces show these men are Yorubas, the tribe from which Chief Awolowo draws his strength. The inexpensive cloth and soiled appearance of their traditional agbades (capes), bubas (shirts) , and soros (pants) indicate they are the farmers, the laborers, the poor and illiterate of Ede. The stage is set for the type of ''grass-roots organizing'' NPN hopes will provide them a victory.

Another obstacle in Shagari's task of nation building -appears as the crowd parts and the imam of Ede, a towering Muslim holy man, strides forward. His presence points out the religious division between the predominantly Muslim north and the Christian south. Nearly 7 feet tall in his celery-colored agbade, he gazes from below the rim of a maroon cap wrapped in white chiffon that falls gracefully about his shoulders. A frail, toothless man holding two microphones hands one to the imam.

Suddenly the air comes alive. Each stream of the holy man's Arabic intonations is translated into Yoruba through the toothless grin of the little man. In the crowd, Christians place their palms together in prayer, while Muslims extend their hands, palms up. Chants of ''Ame, Ame'' accept the imam's prayer of success for Shagari, the NPN, and each individual in the election. The chant climaxes as hundreds of voices fall silent.

Serious politicking begins with introductions of the state chairman of NPN and his entourage. Each receives a rousing ''One Nigeria!,'' prompted by a young secret service-type Nigerian sporting Western dress, sunglasses, and a tape recorder. The political meat of the campaign follows. Promises of increased agricultural production, new industries, a new school for Ede, and no flat-rate tax on the poor bring murmurs of approval. A second gift, two calabashes containing food, are presented to NPN by the Oba. It's a good sign. In Nigeria, they could have contained blood or a weapon, a symbol indicating the NPN was not welcome in the area.

The state chairman graciously accepts the gifts. Taking the microphone, he steps into the circle of men, their faces squinting in the afternoon glare. The richness of his expensive lace clothing clearly sets him apart from those to whom he so carefully explains the failures of the Unity Party of Nigeria. His active dialogue with those in the audience, the shouts of ''One Nigeria!,'' and the intensity with which the men listen in the heat attest to his effectiveness as a speaker. The slow singsong intonations of his native Yoruba tongue seem to lull the crowd.

Then, his pitch begins to build. Slowly, almost imperceptibly at first, a low roar forms in the throats of the crowd. The crescendo builds, breaking into the triumphant chant ''One Nigeria, One Nation, One Nigeria, One Nation!'' More gunshots crack the air as the talking drums erupt in a luring rhythm that reaches into the crowd. Everyone, politicians and townspeople alike, dances to this rhythm that Africa hears - the one Shagari and the NPN hope will unite their people as ''One Nigeria.''