Obasanjo, still a key power broker in the ruling Peoples Democratic Party (PDP), has launched a series of scathing attacks against Jonathan in recent months and has publicly urged him to not seek re-election -- calls the president has ignored.
"Initially President Jonathan's understanding of the Boko Haram phenomenon suffered from wrong reading and wrong imputation," Obasanjo said at a book launch event late yesterday.
"That is what led us to where we are today."
Jonathan has been roundly criticised for his handling of the Boko Haram conflict but the comments from Obasanjo may take on added significance with less than three months before Nigeria's vote.
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Obasanjo plucked Jonathan from relative political obscurity to serve as Umaru Musa Yar'Adua's running mate in 2007 polls.
Jonathan rose to the top after Yar'Adua's death in 2010 following an illness.
Obasanjo called on Jonathan, a southern Christian, to stand aside before the 2015 polls in favour of a Muslim from the north to preserve the PDPs unwritten rule of rotating power in the divided nation.
But in yesterday's speech, Obasanjo appeared intent on continuing his attacks.
He also slammed the president's economic management, saying that if Nigeria stays on its current course and fails to contain graft, "we will all sink deeper into poverty".