US President Barack Obama heads for his first major tour of Africa this week as the continent's anti-apartheid icon Nelson Mandela lies critically ill, making it uncertain whether the world's most famous black presidents will meet.
And as he journeys through Senegal, South Africa and Tanzania from Wednesday, touting trade, investment and the developmental benefits of democracy, he must fix the perception that he has given the region short shrift.
"Africans were very excited when President Obama was elected," said Mwangi Kimenyi, a senior fellow at the Brookings Institution.
"They expected deeper engagement than in the past, both in regard to policy and also in terms of actual visits to the continent given the president's African heritage."
Obama hardly dampened expectations, declaring in a quick stop in Ghana in 2009: "I have the blood of Africa within me, and my family's own story encompasses both the tragedies and triumphs of the larger African story."
But Africa policy has languished, with Obama battling economic tumult, rebalancing US attention to a rising Asia, being outpaced by revolution in the Middle East and consumed by his legacy project of ending US wars abroad.
Still, White House aides feel a nagging call to Africa, and Obama will head there this week.
"Frankly, Africa is a place that we had not yet been able to devote significant presidential time and attention to," said Ben Rhodes, a deputy US national security advisor.
One hotly anticipated moment of the visit is suddenly uncertain, with Nelson Mandela's fragile condition possibly scuttling a meeting between the first black presidents of both South Africa and the United States.
The men met in 2005, when the former South African president was in Washington, and the two have spoken several times since on the telephone.
But there have been no face-to-face meeting since Obama was elected president in 2008. The White House has said it will defer to Mandela's family regarding any meeting.
US officials are aware that emerging economic opportunities and energy resources in Africa have attracted a clutch of interest from rising rivals.
"There are other countries getting in the game in Africa -- China, Brazil, Turkey," said Rhodes.
"If the US is not leading in Africa, we're going to fall behind in a very important region of the world."
Washington noticed that new Chinese President Xi Jinping professed a "sincere friendship" with Africa when he visited the continent on his first foreign tour.
Talk of a new "great game" for Africa with Beijing might be overcooked, but Obama may subtly play on concerns over China's aggressive economic tactics.
He will likely stress a US record in building local expertise, transferring technologies, transparency and the power of American brands, and stress economic "rules of the road" -- a frequent US bone of contention with Beijing.
Obama may also suffer from comparison to George W. Bush, who made an Africa tour in his first term and who -- despite a checkered presidential legacy -- is revered for his HIV/AIDS program which saved millions.
While President Obama has largely been a stranger in Africa, his interest in the region has been evident -- but has garnered few headlines.
In an unusual intervention in a foreign election, Obama in February urged the people of Kenya, the homeland of his late father, to avoid a repeat of violence that killed more than 1,000 people after 2007 polls.
That violence led to the indictment of Kenyan President Uhuru Kenyatta at the International Criminal Court in the Hague, making it politically impossible for Obama to pay an evocative trip to Kenya on this tour.
From afar, Obama courted nations who embody US hopes for democracy and good governance. He invited African leaders to the G8 summit in Camp David last year to launch a new food security and nutrition plan.
Obama also intervened in the Sudan crisis, hosting rival leaders at the United Nations in 2010 in a bid to save the peace process.
He sent US special forces troops to the Central Africa Republic to train forces hunting messianic warlord Joseph Kony.
Other US military operations in Africa have meanwhile multiplied, as terror franchises have exploited instability in Mali. US drones keep a stealthy vigil from bases in Ethiopia, Niger and Djibouti.
US officials, however, deny Obama has over-militarized Africa policy.
"Advancing peace and security is a core objective for US policy," said Grant Harris, senior director for African Affairs on the National Security Council.
"But it's part of a holistic approach of strengthening democratic institutions, spurring economic growth, trade and investment, and promoting opportunity and development."
While arm's length policy action can be effective, the true stamp of presidential intent only comes when Air Force One touches down on foreign soil.