The announcement by Iran's government that they will be stationing "powerful naval forces" off the Atlantic coast of the US may seem at first to be laughable. After all, their navy is small and it's largest naval vessel is a destroyer. They even have significant numbers of WW2 US vessels in their inventory. Predictably, US naval officer were quick to dismiss any threat.
For all our sakes, let's hope that this reaction does not reflect the US Navy's real evaluation of the threat. Forget the surface ships. The biggest worry in the Iranian subs, many of which were bought from Russia. These are diesel powered and are very quiet when running submerged. In addition, as we demonstrated after WW2, it is easy to modify an attack sub to launch cruise missiles. It may even be possible to use them to launch ballistic missiles by towing them in a "submarine trailer" that surfaces just before launch. In the final days of WW2 the German's designed such devices to enable missile launches on the US mainland.
Iran is also on the brink of developing nuclear weapons. Three weapons detonated at the right altitude and in the right locations above the US would blanket the whole country with an Electromagnetic Pulse (EMP) that could kill the electrical grid and solid state electronics, instantly returning us to the mid-1800's.
Add to this the fact that the Iranian theocracy may just do this even if they know we will retaliate and the potential danger becomes very real. I only hope that our defense department has learned to think "outside the box".