I don't usually like commentators writing the speech that they think politicians should give*, but I'll make an exception for Fareed Zakaria, whose piece on PostGlobal channels Obama addressing Iraq. Zakaria's speech would be a way for Obama to back off his withdraw-at-once position, and to acknowledge the changes the last year or so has brought. I don't really care about Obama backing out of public financing, or going negative in his campaign. All that's part of electoral politics, and the ugly reality is that anyone who doesn't jump all over every advantage in a campaign probably won't be president. However, on a vital issue of policy like Iraq, if Obama is unwilling to reexamine his past position, you have to wonder what his promises to be a different sort of politician actually amount to. That doesn't mean Obama needs to abandon his call for a withdrawal, but he does need to explain his position within the changing context.
*Unless, of course, they're satirical. For instance, a McCain speech on age, before an MTV audience: "Good afternoon. It's great to be here. I know a lot of you are concerned about electing a man who could reach 80 years before leaving the White House. You can all go to hell. I was kicking ass while your parents were still in diapers. Buncha punks. God bless America!"