William Safire has a piece republished in Front Page on a rather unpleasant side of Harry Truman. As Safire correctly sees, though, Truman managed to divorce his anti-Semitic and anti-black personal feelings from what he decided was the right thing to do--for example, integrating the Army and recognizing the statehood of Israel. You might call him a reformed segregationist, something like George Wallace when he was governor of Alabama in the late seventies and early eighties.
I always believed Wallace really had a change of heart and I think that the assassination attempt that left him incontinent in a wheelchair had a lot to do with it. I think Truman had some kind of change of heart, too, though as an old man in the Sixties he did not approve of the civil rights movement. Even if Truman never changed his ideas at heart about Jews and blacks, he was wise enough to overcome said ideas for the good of the country.