One of the ongoing (and therefore continually implicit) demands for policy change in the U.S. from Islamic fundamentalists has been "stop supporting Israel." An attack like this could have been executed to prove to the most powerful nation in the world that even they are not invulnerable to "the Wrath of Allah," as the zealots would put it.

Of course, it could also have been done as revenge. If it was Qadaffi, this would be revenge for the killing of his family members in the bombing of Libya years ago.

IMHO of course, and I'm not an informed political scientist or strategic studies expert.