AMERICAblog provides it concisely:

"But Iraq, my dear neo-con editorial page editor Mr. Hiatt, is Terri Schiavo. All the king's horses and all the king's men aren't going to be able to put Humpty Dumpty back to together again. Schiavo's life was over. Iraq is a goner. Pulling the plug sucks, we get that. But sometimes pulling the plug is the only option left."