Proponents of a high rise bridge say it would be cheaper and actually harder to disable due to a terrorist attack. However a bridge brought down due to determined military action would bottle up much of the Atlantic Fleet.

A collapsed, flooded tunnel will not prevent warships from passing over it, however a collapsed bridge could block the channel.

Let us not forget, that when the huge Charleston Naval Base was closed down, one of the justifications for its closure was that the ships based there had to go under a bridge to get to open water.