The first family is departing Wednesday for a weeklong trip to Senegal, South Africa and Tanzania to promote democracy and economic opportunities. Obama has only visited sub-Saharan Africa once before as president, a brief stop in Ghana in 2009.
In South Africa, Mandela is hospitalized in critical condition. White House advisers say they will defer to the anti-apartheid leader's family on whether he's up for a visit from Obama.
Missing from the itinerary is Kenya, the home of Obama's late father, where many of his relatives reside. Kenya's new president is facing war crimes charges, making it an awkward time for a visit.