The 69-year-old is a Muslim from the northern Nigerian state of Niger.

Informal rules

Because of informal election rules, his ambition to run for president poses a threat to any ambition by Jonathan, a Christian from the southern Niger Delta, to seek re-election in the polls due in January.

An unwritten agreement in the ruling People's Democratic Party (PDP) says power should rotate between the Muslim north and Christian south every two terms, meaning the next president should be a northerner if the principle is maintained.

"Even if there are people within the party supporting Babangida, the party will be split."

Patrick Wilmot,
political commentator

But PDP said on Thursday that Jonathan has the right to contest the election, because the unusual circumstances in which he took over the presidency warranted a suspension of the zoning rules.

Jonathan was sworn in as president in May after Umaru Yar'Adua, his predecessor, died of illness part way through his first term.

Jonathan has not yet said whether he plans to stand, but a bid would need the support of northerners within the PDP to be guaranteed victory in the polls.

Atiku Abubakar, a Muslim from the north and former Nigerian vice-president, has also declared his intention to seek the PDP nomination.

Yar'Adua had left Nigeria for medical treatment in November, and power was transferred to Jonathan, then vice-president, in February after rounds of legal wrangling.

'No consensus'

A military ruler has managed to return to power in Nigeria in the past.

Olusegun Obasanjo, an army general, ruled the country from 1976 to 1979. He was then elected as president in 1999 and stayed in power until 2007.

"There was a consensus, among the people in the north especially, that Obasanjo should be elected," Patrick Wilmot, a Nigerian writer and political commentator on African affairs in the UK, told Al Jazeera.

"But with Babangida there's no such consensus.

"I am surprised that he decided to run because the ruling party has already said that the incumbent president can run.

"Even if there are people within the party supporting Babangida, the party will be split."