I'm in the process of moving and I haven't kept up, but my guess is that he's LYING.
Why didn't he come forward the day AFTER the President's State of the Union address???? If he says he KNEW i to be false then, he was derelict in not coming forward sooner.
Joseph Wilson has made several speaches that were titled "The case against regime change in Iraq", I saw this guy Wilson on the Phil Donahue show participating in a town hall meeting right before the war started, and he was trashing the president and never mentioned this information about Niger at all. He was mainly claiming it was all about oil and ....... Well! you know the rest.