Two simple posters explain the civil war in Nigeria. The first, a thin strip, was glued to the walls and windows of most public buildings in Enugu, the capital of Eastern Nigeria, a few weeks before the region seceded on May 30 to become the Republic of Biafra. The poster shows four men. Three look alike, obviously Ibos, the dominant tribe of the east. The fourth man is a Hausa from Northern Nigeria. “This Is Your Region,” the poster says, “Report Any Strange Face to the Police.”

The second poster, a little larger and more colorful, was slapped all over Lagos, the federal capital of Nigeria, a few weeks before federal troops invaded Biafra on July 6, the beginning of the civil war. This poster shows a monstrous drawing of the severed head of Col. Odumegwu Ojukwu, the ruler of Biafra, lying under the heavy combat boot of a Nigerian soldier. “Crush Rebellion,” the poster says.

The first poster reflects the intense tribal feeling of the Ibos of Eastern Nigeria. They are enraged and bitter over the massacre of thousands of Ibos in Northern Nigeria last year. They believe the other tribes of Nigeria would wipe them out if they could. For this reason, the Ibos feel they are fighting for their survival.

But in Lagos, just 270 miles from Iboland, the federal military rulers and their civil servants, now mostly from the north, refuse to acknowledge that this emotionalism exists. In their view, as the second poster shows, a gangster named Ojukwu is stirring up the Ibos. Crush them, and all the problems of Nigeria go away.

This fear and distrust and resentment and rage in the Ibos and the federal government’s failure to understand or even acknowledge it are the reasons why Nigeria, the most populous country in Africa, and potentially one of the richest, is destroying itself in civil war. It is also why the federal government believed, at the beginning, that it could march into Enugu swiftly and cleanly, string up Ojukwu, and end the secession. The resistance of Ibo civilians has astonished the federal government, bogged down the federal army, and perhaps presaged a long, bloody and tormenting guerrilla war, like that in Vietnam.

The roots of the civil war go back to the coup of January 15, 1966, when young officers of the Nigerian army overthrew the government and murdered several leading politicians, including Prime Minister Abubakar Tafawa Balewa and the northern regional leader, the Sardauna of Sokoto, probably the most powerful politician in the country. Although many of the young officers were Ibo, it was not an Ibo coup. The plotters came from the large class of educated young men, mostly southerners, who were incensed at that time over the inefficiency, greed and corruption of the politicians and over the domination by the Moslem, backward, feudal northern region. Most southern tribesmen, whether Ibo or not, rejoiced over the uprising. The young officers had planned to form a government led by Chief Obafemi Awolowo, the old Yoruba leader, who had been jailed by the federal government on charges of plotting its overthrow. But Major General Aguiysi Ironsi, the Ibo who commanded the army, stepped in to end the young officers’ coup and take over the government itself.

During Ironsi’s reign, many of the key jobs in government went to Ibos; mostly because of their ability but partly because of their clannishness, one Ibo making sure another filled the opening in a ministry. The Ibos’ aggressiveness in the new government intensified the dislike that most tribes in Nigeria had for Ibos for many years.

The Ibos like to think of themselves as the Jews of Africa. They are a hard-working, aggressive people, with a thirst for education and its rewards, a willingness to take any job anywhere if it seems to lead to something better and, perhaps most important and most unusual in Africa, an avid acceptance of new techniques and ideas. Unlike the case in most African tribes, status in traditional Ibo society depended on what a man achieved in his lifetime, not on his inherited titles, caste or wealth. In that kind of achieving society, individuals usually have freedom to try new ways to get ahead and win status.

When colonialism came, the Ibos quickly accepted Christian missionaries and their schools, recognizing this new way to achieve status. Over the years, Ibos became the professionals, the foremen, the businessmen and the skilled artisans of Nigeria. This was particularly true in Northern Nigeria, so backward that it had to depend on outsiders—Ibos and Europeans—to run its railroads, its shops, its schools, its offices. Like the Jews of Harlem or the Asians of East Africa or the Chinese of Southeast Asia, the Ibos were the prominent outsiders in the economic life of the dominant population and, like the others, they were hated.

On July 29, 1966, northern officers of the army staged a second coup, killing Ironsi and a good number of Ibo officers. Lt. Col. Yakubu Gowon, a 31-year-old Christian of a minority tribe in the north, took over the government. Two months later, Hausas and other northern tribesmen struck out at the Ibos in their midst.

The Ibos say that 30,000 were killed in this massacre, which Biafra now calls the “Nigerian pogrom.” According to photographs published by the eastern region, Ibos were decapitated, dismembered, gouged, emasculated and burned alive. The northerners used guns, daggers, machetes, axes, sticks, bayonets and spears to flail, maim and kill their victims. Almost 2 million Ibos left their homes and businesses throughout Nigeria and returned to their tribal homeland in Eastern Nigeria. It was clear to them that there was no safety for them in the rest of Nigeria.

The massacre made it impossible for Nigeria to stay together as a federation, for the Ibos now refused to take part in any political arrangement that failed to give them full control over their security and their future. In the eight months between the massacre and the secession, there was some chance of working out a confederation that gave the Ibos sovereignty yet kept the regions together in an economic union. But, for several reasons, the chance was squandered.

The federal failure to sense the depth of anger in the east was the most important. The Ibos just seemed unreasonable to officials in Lagos. “Why don’t they let bygones be bygones?” one official asked me, as if the Ibos were children nursing a grudge over a harmless prank. To make matters worse, federal officials, especially northerners, never seemed contrite about the massacre. They might begin a conversation by muttering how terrible it was, but they would spend most of their time explaining it away. The usual line was that the Ibos, killing northerners in the first coup, brought the terrible retaliation on themselves. In short, everything was fair and square now—a few northerners killed, 30,000 Ibos killed. Bygones should be bygones.

The personality of Ojukwu also hampered negotiations. A cultured, wealthy graduate of Oxford, Ojukwu overshadowed Gowon and the other military governors of Nigeria. Unlike the others, Ojukwu behaved like a politician with a flair for public relations. And, at negotiations in Aburi, Ghana, in January, Ojukwu simply outmaneuvered Gowon and the military governors of the other regions and persuaded them to accept most of his proposals for a future confederation of Nigeria. Later, when they realized what they had accepted, Gowon and the others reneged, pleading that they had come to the conference unprepared. After that, Ojukwu, whenever he discussed Gowon and the others with newsmen, talked of them with contempt and despair; he made it clear he did not suffer fools gladly. Ojukwu’s contempt was very evident to Gowon and the others, and their resentment intensified to the point where they began to see Ojukwu alone as the cause of all their troubles. They never understood that Ojukwu simply reflected and guided the angry emotionalism of his people; in fact, he probably was even more moderate than many of his lieutenants.

Finally, influential people persuaded Gowon to do all he could to keep Nigeria together under a strong federal government. They argued that giving in to Ojukwu’s plan for a confederation would destroy Nigeria. The most prominent of these people were the federal civil servants who had taken advantage of the absence of politicians and the inexperience of the soldiers to run the day-to-day operation of the country. These federal officials were joined by diplomats of the U. S. Embassy and the British High Commission who believed in a big Nigeria and, sitting in Lagos, also failed to understand how the mas- sacre had turned the Ibos into a bitter and chauvinistic people.

With the eastern region refusing to accept more than the most tenuous ties with Lagos, and the federal government refusing to let go that much, secession and civil war became inevitable. Adopting the strains of “Finlandia” as their national anthem, the Ibos seceded and proclaimed the new Republic of Biafra. A few weeks later, Gowon’s forces invaded, intent on crushing “Ojukwu and his rebel gang.”

The pace and progress of the war is difficult to assess. Both sides put out lying war communiques and, in the main, refuse to let newsmen verify the claims. But out of the tangle of confusing claims and counter- claims, a few points seem clear: this is a war of tiny armies, a few thousand on each side. Most of the people of Nigeria step out of the way when troops approach, and let them take over. The only exceptions are the Ibo civilians who resist with fervor and bitterness. As a result, a few federal troops can move in a non-Ibo area of Biafra with ease. And, in fact, the Biafrans, in their takeover of the midwestern region, showed that it is not too difficult for them to take over territory outside their region. But no federal army, no matter how great, no matter how much support it has from Soviet MIGs, can move with ease in Iboland. The Ibos are too tenacious and too committed; in short, the federal government, if it is to succeed, must fight for Iboland inch by inch. And, if it is successful, the federal government must be prepared to occupy Iboland as if it were enemy territory.

In many ways the civil war is pointless, for Nigeria has never been a nation; it exists only because some white men, in an almost playful mood, sat down at the turn of the century and drew some lines on a vague map. One British negotiator, who was present when the British, French and Germans split up their colonial prizes, recalled that “in those days, we just took a blue pencil and a rule and we put it down at old Calabar and drew that line up to Yola.” “We have been giving away mountains and rivers and lakes to one another,” another negotiator, Lord Salisbury, once recalled, “only hindered by the small impediment that we never knew exactly where the mountains and rivers and lakes were." Nigeria, as administered by the British, made no sense as a geographic, historical or ethnic unit. In fact, the British did not even rule it as a single unit until 1914. This amalgamation, which combined the Islamic north with the Christian and pagan south, was something like putting Egypt and Ireland together and calling the combination a nation.

Despite the obvious lack of a Nigerian nationalism, most African countries publicly support the federal government in its attempt to end the secession. There are so many secessionist movements in Africa—almost all a legacy of colonialism—that African leaders fear the success of one might ignite the others and lead to continental chaos. If Biafra succeeds, so might Eritrea in Ethiopia, Buganda in Uganda, the northern frontier district in Kenya, Katanga in the Congo, or the Casamance in Senegal. There is a measure of justification for their fear. Yet the special circumstances of the war—the intense tribal feeling of the Ibos and the hatred of the other tribes for them—seem to be persuading at least a few Africans to push aside their fears and show a bit of sympathy for Biafra. The African editors of The Daily Nation in Nairobi and of The Tanzanian Nationalist in Dar es Salaam, for example, have written editorials questioning the policies of the federal government.

The United States. however, has never seemed to question federal policies. The embassy in Lagos has consistently encouraged the federal government to take all measures to preserve the federation. Once the federal government seemed intent on crushing the secession by force, the embassy adopted a policy of keeping its hands off and its mouth shut in public. This, of course, was a silent way of showing its approval.

It's hard to indict the State Department, however, for encouraging the federal government to take a course that it probably would have taken no matter what it heard from the Americans. Moreover, when Gowon asked American dealers to sell him arms, the State Department rightly refused to grant them an export license.

But the Americans can be indicted for, first, failing to understand the mood and determination of the Ibos and, second, for failing to use their influence to encourage the federal government to face realities and negotiate with the Biafrans for a confederation.

Is a negotiated settlement possible now? The bloodletting may have stirred hatred so deeply as to make it impossible. But, in the event of negotiation, a settlement can come only if the federal government accepts a loose confederation in which it would have little more power than that of representing the various regions in the United Nations. In exchange for this, Biafra likely would have to agree to participate in an economic union, which distributed a share of Biafra’s ample oil revenues to the rest of the confederation.

Without negotiations, the future seems clear. If Biafra wins the war, Nigeria will split into several pieces. If the federal government wins, the Ibos will become a maimed and occupied people. In either case, civil war will not make a nation out of Nigeria.

Mr. Meisler, Africa correspondent of the Los Angeles Times, is a frequent contributor to The Nation.