There's very little clandestine in nukes. I would hope our intelligence forces as well as those of Israel (who'd probably be the intended target) would know full well the signature of any major explosion.

Building a nuke isn't this tiny little operation. Too much goes into it. Huge research and processing facilities, tons of scientists, and tons of money. That last factor makes hiding their existance in this world a very tough thing.

Even if a country thought they could get away with not being fingered for the initial attack, they'd have to worry about the irrational response from an angered world. The nuclear powers may simply assume the country of origin to be Iran and go after them even without clear proof.

In many ways Iran's nuclear posturing is probably bringing delight to the hard right in Israel and the United States. They now have the justification they want, should any terrorist ever smuggle an atomic weapon into Israel and set it off. Even if Iranians are not behind it, they could easily rationalize a devastating nuclear attack against them.

Art