It occurs to me that, even supposing the structural issues of a Space Elevator are solved, the matter of defending it would pose a challenge half as steep as building the thing.
You have a structure that is known throughout the entire world
, extending to a height far above that of any modern tower, such that it can be approached by anyone and attacked at any point along its length, including regions far above the range of any known aircraft, such that if one were to launch an ICBM
from any silo on earth, it would be able to hit the elevator in a region no human military has ever been able to defend.It is enough of a challenge to defend a railway
that lies flat on the ground. Imagine trying to do that for one that goes straight up, and falls apart completely if any of it does, and goes places a weapon can but a defender can't. The military logistics
of trying to defend such a thing seem like they would be a nightmare.
That is, defending it at the point of it being attacked, which is, being the last line of defense, not something you want to rely on. Presumably the structure can be protected by protecting its idea -- to my mind, most easily achieved by making it a shared possession of the entire world, such that no specific nation can put it to an exclusive use that would invite envy. But you would need to defend against the people who DID want to have it all for themselves, as well as the people who are simply out for destruction
The total cost of defending such a thing might cause the greater portion of the world to be involved in keeping it alive. Which is, I should think, a wonderful hook to hang a sci-fi story on...
As long as that story also deals with the threat of weather patterns. Imagine throwing every airplane you have into patrolling the elevator and then losing the whole thing to a thunderstorm.
There are a ton of questions involved in the existence of a stable Space Elevator whose answers would tell you how the story's setting works.
As for reality -- I would be much happier to have an anti-gravity system that lifts discrete payloads on its own, without needing a workable physical structure from here to orbit. That would be SO much more simple. Less impressive, of course, less flashy. But if you're going to space, Aesthetic is among the weights you must leave behind. In space there is not a bit of room for Aesthetic, because if you fail, you don't get to just sit on the ground and cry. You die.
The idea of a Space Elevator seems like it is mostly for the sake of pointing at it and saying "look what we built". For all practical matters, choose Cavorite.