One issue above all else has gripped Nigerian political life. It dominates the front pages of newspapers each day, and has done so for months.
By Alex Last
BBC News, Lagos
Mr Obasanjo has not publicly said whether he wants to remain in office
The issue is "the third term". Should the constitution be changed to allow President Olusegun Obasanjo to run for a third term in office? Will he run if he gets the chance?
Given Nigeria's history of military dictatorships, the political ambitions of the country's leaders are scrutinised intensely.
Under current Nigerian law, President Obasanjo is due to stand down in May 2007 at the end of his two terms in office.
But the National Assembly is considering an amendment to the constitution which would allow the president to run for a third term in office.
President Obasanjo, who himself headed a military government in the 1970s, has studiously avoided stating his intentions.
In a recent interview he said he would decide whether to run, if the constitution was amended.
This has hardly dampened expectations. The obvious question is why amend the constitution if the president does not want to stay in office?
His supporters have been very publicly campaigning for the third term. They argue he should stay in office because he's the only one who can reform Nigeria.
"There are three reasons I want the president to stand again: the economy, stability and a united Nigeria, which he has been fighting for all his life," says Njidda Gella, a pro-third term member of the House of Representatives.
"We have a mutilated constitution that requires amendment. We need to amend it for democracy to be sustained in Nigeria. President Obasanjo is not clinging to power; he's trying to make Nigeria great."
But opposition to the third term is strong and widespread. The vice-president, state governors, leading politicians, civil rights groups, even some religious leaders have come out in opposition.
They say a third term is a dangerous move towards a civilian dictatorship.
Vice-President Atiku Abubakar, who wants the top job in 2007, recently came to the fore in the anti third term campaign - a move which has brought him into open conflict with the presidency.
"We have seen how tinkering with the constitution to allow for tenure elongation in some African countries led to sit-tight dictatorships," he told supporters at a recent rally.
"This is exactly what is going to happen if you, the people, allow this constitutional amendment to pass through the national assembly."
Religion and ethnicity are also factors. President Obasanjo is a Christian Yoruba from the south-west.
The oil-rich south has yet to produce a president
Other regions feel it is now the turn of one of their leaders to run the country.
That feeling is particularly strong in the mainly Muslim north, from where the vice-president hails, but is also a demand of many in the oil-rich far south of the country, a region which has never produced a Nigerian president.
There are fears both inside Nigeria and abroad that given the scale of opposition, allowing a third term could destabilise the country.
In the last few months there have been militant attacks on the oil industry, as well as vicious political and sectarian riots: Not good omens for next year's elections.
Testifying before a senate committee, the US intelligence chief, John Negroponte, said if a third term went ahead Nigeria could be plunged into major turmoil.
Such chaos, he said, "could lead to disruption of oil supply, secessionist moves by regional governments, major refugee flows, and instability elsewhere in West Africa."
For the amendment to become law it needs the support of two-thirds of both houses of the National Assembly, and the backing of 24 of Nigeria's 36 states.
Pro-third term politicians are confident they will get the votes needed. But opposition leaders say they have enough to block any amendment. It looks as though it could be close.
There are intense efforts to muster the numbers both for and against the amendment.
There have been accusations of bribery to win over legislators.
For months, opposition leaders and civil rights groups have accused the government of using its anti-corruption campaign to target opponents of the third term.
For the amendment to pass, a lot will depend on the strength of the political networks of the two camps and the wealth and loyalty commanded by each side's political patrons.
To an extent, this is a struggle between political elites.
Sources say many of the political grandees who helped put Mr Obasanjo into office in 1999 feel the president has turned his back on them and do not want to see him stay in power.
But they are now faced by those who did do well during the president's tenure.
Being on the winning side is crucial in Nigeria. Political power means control of the country's huge oil wealth.
In the country's few attempts at democracy, an incumbent president has never officially lost an election.
The third term debate will determine who will stand, and probably who will win next year's election.
It is a struggle over the political future of Africa's most populous nation. The battle lines have been drawn.