WASHINGTON (CNN) -- Sen. Barack Obama, D-Illinois, told CNN Monday he is not sure when he will decide on a White House run but expressed confidence that the American people are ready to elect an African-American as their leader.

"I think the American people at their core are a decent people," the Senate's lone African-American member told CNN's Don Lemon. "I think we still have prejudice in our midst, but I think the vast majority of Americans are willing to judge people on the basis of, you know, their ideas and their character."

Obama also said he hasn't set a timetable to decide on a run for the White House but acknowledged he will have to decide in the near future.

"External circumstances and the campaign calendar impose a certain limit on how long it would take for me to make a decision, but at some point I'll make it, and I promise when I do, I'll talk to CNN," Obama said.

-- CNN Ticker Producer Alexander Mooney