Moreover, it would happen before anyone knew what happened.
Here's a guess at what the media (and the rest of us) would see:
-Communications from Tel Aviv cease abruptly
-A few minutes later, indications show that a nuclear weapon went off in the city center
-15 to 20 minutes later, data from USGS website show unusual seismic events in Iran.
-President and some Air Force generals explain via a television broadcast a few hours later that radar detected an unexpected suborbital launch in Iran. Once it was clear that a nuclear attack had occured, certain treaty obligations were invoked and the aggressor was punished in such a way that it will no longer pose a threat.
Yep, it would be a lot like that. Except don't expect the USA to push the button.
I don't.
I think we would be greeted with sucide attacks all over this country in the days following any major/nuclear attack on Iran.
That doesn't mean I don't think we shouldn't attack, we definitely must respond. But we must also be ready for the attacks on our civilian populace here at home by sleeper cells.
Maybe it means that many of us have to start carrying weapons for our own defense.