In the past three Israeli operations in the region - 2006, 2008, 2012 - there have been no military reactions by any of the players Morris mentions. Furthermore, the intl. community did not come down on the side of Hamas or Hezbollah in these cases. Iran has more to lose by attacking Israel. The sympathy gained through in the wake of a pre-emptive Israeli attack suits their needs more - an easing of sanctions and a lifting of the diplomatic pressure.
World Jewish Congress: Nazi train treasures must go to rightful owners (Reuters)
from the article: The day after Iran's tomorrow