Just for fun, let's look at it from Iran's viewpoint. They now have many and large bases of Americans on their eastern border in Afghanistan, and ditto for their Western border with Iraq. Americans have both tactical and strategic nuclear arsenals, plus depleted uranium "Bunker Busters" that they tested in the Israeli invasion of Lebanon. We are now trying to "perfect" these bunker busters, as the article points out, to the extent of developing a bunker buster with the weight of 15 small automobiles. Nobody is even guessing where these will first be used. To Iran's South they have the Israeli Nuclear force with every weapon the Americans have. Russia, no friend of Iran, is to the North. There is also the American nuclear fleet off their shores in the Persian Gulf.
First refugees travelling on Hungarian bus arrive at Austrian border (Reuters)
from the article: Iran atomic chief: Tehran to initiate 2 new nuclear sites this year