JOHANNESBURG (AP) _ President Barack Obama promised to visit his father's homeland _ Kenya _ before the end of his presidency, but of the 51 country visits Obama made the last four years, America's first black president spent less than a day in sub-Saharan Africa. That could now change.

Presidential travel trends suggest Obama is likely to spend more time in Africa in his second term, a presidential historian said. Freed of domestic campaign politics, second-term presidents can travel more in a continent that has less strategic importance than Europe and Asia. A rising terror threat in Mali has also heightened the region's profile.

And then there's the promise: ``I'm positive that before my service as president is completed I will visit Kenya again,'' Obama said in a June 2010 interview with Kenya's state broadcaster.

That statement should mean a lot, because presidents don't make such promises lightly, said Brendon Doherty, an associate professor of political science at the U.S. Naval Academy who studies presidential travel patterns.

``Presidents do take special pleasure in traveling to places where they have ancestral ties,'' Doherty said, noting visits by Presidents Ronald Reagan, Bill Clinton and even Obama to Ireland, where each had family ties. ``Given the large role that Africa plays in the family history of President Obama, I'd be really surprised if he didn't travel there in the second term.''

Both Clinton and President George W. Bush took extended trips through Africa in their second terms. Clinton visited six countries in sub-Saharan Africa; Bush visited five. Obama's only visit to sub-Saharan Africa as president was a stopover of less than 24 hours in Ghana. While a U.S. Senator, Obama visited Ethiopia and Kenya, where he has several relatives.

``He is a Kenyan who many people want to see in person. I am proud that he is a Kenyan and that he is the president of a superpower,'' said Sam Ochieng, a political leader in Nairobi's largest slum, Kibera.

Laura Seay, assistant professor of political science at Morehouse College who runs a blog called Texas in Africa, said Africa is a low priority for most American presidents because of geopolitical interests and historical ties, ``and that was the case in the Obama administration.'' She added, though, that Africa is becoming more important to U.S. foreign policy interests.

Even that one trip to Ghana was better than some predecessors. Clinton did not travel to sub-Saharan Africa in his first term, and Reagan never did. President George H.W. Bush traveled to Somalia; President Jimmy Carter, the first president to go to sub-Saharan Africa while in office, traveled to Nigeria.

An Associated Press review of presidential travel shows Europe and North America got the most visits during the Carter-to-Obama period. France led with 24 visits; the U.K. had 23; Canada and Germany had 20; Mexico and Italy had 19.

J. Peter Pham, an Africa specialist at the Atlantic Council, a Washington, D.C. think tank, noted that Secretary of State Hillary Clinton made Africa a diplomatic priority in Obama's first term, visiting 23 of the continent's 54 countries. Pham said Obama has yet to fully deploy ``the immense personal capital'' he has on reserve in Africa.

The White House and State Department declined to comment on whether Obama will spend more time in Africa. Johnnie Carson, the State Department's top Africa official, said this month that the Obama administration has helped Somalia stabilize and South Sudan gain independence and that the U.S. has provided more aid to Africa the last four years than any other country.

Obama's national security adviser said in November that the president's time is the White House's most valuable resource, and Doherty said Obama's lack of time in Africa reflects compelling global priorities, not a lack of importance for Africa.

Though Obama's father is Kenyan, there is a perception that the younger George W. Bush did a lot more for Africa and Africans, said Seay, especially after the creation of the United States President's Emergency Plan for AIDS Relief, known as PEPFAR, a $15 billion commitment to fight HIV/AIDS.

But even if Obama hopes to visit his father's homeland, he may not be able to politically if Kenya's March presidential election turns as violent as the last one. One top presidential contender faces trial at the International Criminal Court over accusations he orchestrated tribal violence that killed more than 1,000 Kenyans in 2007-08.

``It's certainly the case that presidents of both parties spend more time in countries that have long traditions of clean democratic elections,'' said Doherty, the author of ``The Rise of the President's Permanent Campaign.'' ``I would not be surprised if the aftermath of the Kenyan elections last time added to the president's team's hesitance to send him to Kenya.''

Seay said that if this year's election goes smoothly, she wouldn't be surprised if Obama visits. Many in Kenya would love to see that happen.

``He is a symbol for hope, and a role model for upcoming politicians who can change the way Kenya is run by following his footsteps,'' said Ochieng, the Kenyan political leader. ``Kenyan politicians can learn from Obama that politics should be issue-based, not the tribal kind of politics we practice here.''