WASHINGTON — President Barack Obama is on a three-nation visit to Africa designed to reinvigorate America’s relationship with the continent. Obama is following in the footsteps of recent U.S. presidents who have focused on Africa, even after leaving office.

Obama’s trip to Africa is the latest in a list of visits by American presidents going back 70 years.

Allan Lichtman is a presidential historian and professor at American University.

“So by going to Africa, presidents demonstrate that Africa is not forgotten; that the African people and the African nations are important to the American people and to American policy makers,” he said.

While many presidential visits have focused on humanitarian aid, Obama is focusing on trade, investment and democracy.

Jennifer Cooke of the Center for Strategic and International Studies said Obama is looking to the future.

“Moving beyond some of that long-time commitment on humanitarian issues to a much more upbeat and forward looking engagement that a lot of young people in Africa are looking for,” said Cooke.

President Franklin Roosevelt made trips to North Africa during World War II to meet with allies, including British Prime Minister Winston Churchill.

In 1943 the leaders met in Casablanca and later that year in Cairo to discuss strategy for the wars in Europe and the Pacific.

President Jimmy Carter visited Nigeria and Liberia in 1978.

As a former president, Carter has made many trips to Africa, focusing on diseases, such as river blindness and malaria. The Carter Center’s campaign to eliminate Guinea worm disease is hailed as a major success.

Another former president, Bill Clinton, used his foundation to sponsor humanitarian projects in Africa.

“So you can actually, immediately and directly see the results of your initiatives in Africa. That is more difficult in other parts of the world,” said Professor Lichtman.

Health care experts say George W. Bush’s initiative to fight HIV and AIDS in Africa has saved millions of lives. Since leaving office, Bush and his wife Laura have remained active in African health issues.

Helping people in Africa resonates in a positive way at home.

“It is not only the presidents, it is the U.S. public and U.S. Congress, I think, that sees itself as doing those kinds of things in the world - a moral force for good,” said Cooke.

And that is a legacy many leaders seek.