The build-up to the 2007 elections in Nigeria has seen a fierce challenge by some of the country's major ethnic groups. The South-South region, which includes the oil-rich Niger Delta, has mounted the most vigorous campaign to stake a claim to the presidency in 2007.
The South-South, Southeast and the North have emerged as regions likely to produce the next president of Nigeria in 2007.
The South-South region is made up of minority ethnic groups mainly in the oil-rich Niger Delta. The Southeast region is dominated by ethnic Ibos, and the North has been the dominant force in Nigeria's political landscape.
Northern politicians says they only ceded power to the South in 1999 to appease the South-West, following the cancellation of the 1993 presidential ballot widely believed to have been won by Moshod Abiola, a Yoruba businessman.
Groups in the troubled Niger Delta have become incensed in recent weeks over suggestions they lack quality candidates to fill the top job. A militant delta leader, Mohammed Powell, says the South-South deserves a larger voice in Nigerian politics.
"How many times had the North ruled this country? Several times, the West had ruled, everybody had ruled and you say the Ijaw which is the fourth-largest tribe in Nigeria," he said. "Ijaw has not produced a president, Ijaw had not produced a vice president and you are extracting our oil, extracting our wealth, using the money to do business in this Nigeria and you expect us to be happy? When we talk you send the military against us."
But a political analyst in Abuja, Maxi Okwu, says there is an unhealthy trend for ideology-free politics in Nigeria. He says money, individual self-interest, and ethnicity have emerged as powerful tools for electoral success.
"What I mean by it is unhealthy is that nobody is talking about issues here, nobody is talking about programs. It is this cry; 'it is our turn.' Our turn for what and our turn to do what? Nigerians want specific answers to the national question," said Okwu. "How do we come out of this quagmire; economic and political? How do we move forward? How do we address our imbalanced federation? How do we deal with the situation where the president in a democracy dips his hands into the till and walks away without any apology and then nobody is talking? That is no democracy."
Next year's elections should mark the first time an elected president hands power to another since independence from Britain in 1960.
Okwu says the NIgerian system concentrates too much power in the hands of the president and this he said, has become the magnet that drives the power struggle in Nigeria.
"He who gets Abuja, by which I mean Aso Rock [the presidency], gets everything. There is so much power concentrated in Abuja, Aso Rock. It is a hangover of prolonged military rule. We have a loop-sided federation, in fact a unitary state operating as a federal government," he added.
The parliament last month rejected an amendment to the constitution that that would have allowed Obasanjo to run in elections next year. Analysts say the political scene in Africa's top oil producer has been thrown into a state of flux.
Violence remains a feature of political life in Africa's most populous country and the build-up to the elections has been marred by ethnic clashes and attacks on the oil industry.