I’ve played that tune. I’ve talked of tragedy, of emergency. And it is an emergency when almost 2,000 children in Africa a day die of a mosquito bite; this kind of hemorrhaging of human capital is not something we can accept as normal.

Image Bono Credit... Deirdre O'Callaghan

But as the example of Ghana makes clear, that’s only one chord. Amid poverty and disease are opportunities for investment and growth  investment and growth that won’t eliminate overnight the need for assistance, much as we and Africans yearn for it to end, but that in time can build roads, schools and power grids and propel commerce to the point where aid is replaced by trade pacts, business deals and home-grown income.

President Obama can hasten that day. He knows change won’t come easily. Corruption stalks Africa’s reformers. “If you fight corruption, it fights you back,” a former Nigerian anti-corruption official has said.

From his bully pulpit, the president can take aim at the bullies. Without accountability  no opportunity. If that’s not a maxim, it ought to be. It’s a truism, anyway. The work of the American government’s Millennium Challenge Corporation is founded on that principle, even if it doesn’t put it that bluntly. United States aid dollars increasingly go to countries that use them and don’t blow them. Ghana is one. There’s a growing number of others.

That’s thanks to Africans like John Githongo, the former anticorruption chief of Kenya  a hero of mine who is pioneering a new brand of bottom-up accountability. Efforts like his, which are taking place across the continent, deserve more support. The presidential kind. Then there’s Nigeria’s moral and financial fist  Ngozi Okonjo-Iweala, a managing director of the World Bank and the country’s former finance minister  who is on a quest to help African countries recover stolen assets looted by corrupt officials. And the Extractive Industries Transparency Initiative, which is helping countries like Ghana clean up the oil, gas and mining business, to make sure that profits don’t wind up in the hands of kleptocrats.

Presidential attention would be a shot in the arm for these efforts  an infusion of moral and political amino acids that, by the way, will make aid dollars go further. That should be welcome news to the Group of 8 leaders gathered in Italy to whom Mr. Obama bids a Hawaii-via-Chicago-inflected “arrivederci,” as he leaves for Africa.