Put this in the “it only takes one” column. It was reported in 2005 (see here) that the Iranians have tested detonating a Shahab-3 in high altitude flight. Analysts say this means one thing: airbust.
How bad is it? It’s all in the electromagnetic pulse. Need more convincing?
Here is the gist from a reference noted above: “EMP is one of a smalll number of threats that can hold our society at risk of catastrophic consequences.”
Further
What is different now is that some potential sources of EMP threats are difficult to deter — they can be terrorist groups that have no state identity, have only one or a few weapons, and are motivated to attack the US without regard for their own safety.
Rogue states such as North Korea and Iran, may also be developing the capability to pose an EMP threat to the United States, and may also be unpredictable and difficult to deter.
It should be clear that having a nuclear weapon is no light matter. Iran is a sworn enemy with theological, ideological, and political desire to bring about the destruction of the United States. The United States should not and hopefully will not allow Iran to develop a nuclear bomb.