ABC News reported Tuesday that being the first African-American to have gotten so close to winning the White House has created some additional concerns, officials say.
"There is no question that the possibility of violence directed at presidential candidates, especially Obama, is the elephant in the middle of the room," said Peter Fenn, adjunct professor of political management at George Washington University.
"There is a hypersensitivity about this issue. And in one sense, there should be because you don't want to put the idea out there. But you also get over-analysis, like with Hillary's comments about RFK."
Fenn says that while catching a flight at Dulles International Airport last year, an African-American woman told him Obama, the senator from Illinois, shouldn't run.
"She said, 'They're going to kill him.' African-Americans are more worried about it," Fenn recalled.
Last year, U.S. Homeland Security Secretary Michael Chertoff authorized Secret Service protection for Obama 24 hours a day.