without reading the article i'm only guessing.. nigeria would be eager to drop the peg against the USD because of the 2 years of fixed interest rates set by the reserve bank, otherwise they would simply be switching to the euro.

the only problem in the US atm is that the us govt stopped hiring people from standard and poors during the gfc... not enough people to make the govt's numbers look nice and AAA when they are put into the algorithms they wrote while they were working at s&p's