Because they believed the lies told to the Bush administration about WMD. This is the real travesty.
"It has tormented me, torn me more than any one thing," he said with a grim look on his face. "To see what these guys in Iraq are having to go through and knowing what I know here: that we didn't prepare for it, we didn't understand what we were getting into. And to put those guys in those positions, it makes me so angry."
Got any documentation of the lies?
Yep, that's what happens when you lose your nerve . . . or sniff the political wind.