re: "No terror attacks have succeeded here since 9/11/2001"
You're right, I have no proof... but how hard would it be to have a few snipers on rooftops during a big parade, or in Times Square on New Year's Eve... or a couple of suicide bombers in the NY subway, or at the Superbowl, or a truck bomb at a mall or a school, or.... etc, etc.
Something of the magnitude of the WTC attacks or a major bio release or a suitcase nuke might be harder to pull off, but plain old terror? It would be a snap. The only explanation for it not happening is that the terrorists don't want to do it.