Sam Nunn (D-GA) was the principal congressional Democrat who helped Republicans ambush Bill Clinton over gays in the military in 1993. Now he's saying that Don't Ask Don't Tell is due for a review. He isn't calling for its outright repeal -- he's just saying that "it’s appropriate to take another look at it". That's code for "I want to be Secretary of Defense in a Barack Obama administration, but I would also be willing to be Secretary of Defense in a John McCain administration".
Some may recall his submarine photo-op tours wherein emphasis was placed on how closely sailors bunk near each other. Really closely. Imagine if one of them was, like, gay. Nope, can't allow those gays to be in any military of ours. Ban them, even if they're PhD-level linguists who could have translated Arabic terrorist messages.