In fact, if there's anything that's clear from his interview with the Chicago Tribune (here), it's that the most charitable interpretation of his dealings with Rezko is that Barack misjudged him.
Fair enough. Almost all of us, at one time or another, have trusted someone untrustworthy or made a mistaken assessment of someone's character. The difference, of course, is that we're not running for President on the alleged strength of our "judgment" -- or proposing the kind of personal dialogue with the world's dictators that would, presumably, permit us to form judgments about them and their characters. After Barack's Rezko boo-boo, just how credible would his character appraisal of Mahmoud Ahmadinejad be?