I only read about ICBMs being armed with nuclear warheads. I have never read about them being armed with conventional weapons. So that must mean that the nations that have ICBMs only use them as part of their nuclear armed forces.
Why is this? Why not use ICBMs for conventional reasons?
For one you don’t want people thinking you’re launching nukes.
Other reasons may include them being very expensive and unnecessary compared to conventional arms.
Why would you need to fire it half way across the world when you can do it from a few hundred miles away in the same relative safety.
Some ballistic missiles use conventional warheads. SCUD missiles for example.
Generally ICBMS exist as a strategic deterrence rather a tactical strike platform because the infrastructure needed to generate and support ICBM capability far outweighs their utility for anything other than to offer the spectre of total annihilation.
The payloads of missiles aren’t huge. That’s okay for nuclear weapons which pack a lot of bang per pound, but wouldn’t make sense for chemical explosives.
That being the case, any nation that sees an ICBM coming toward it is going to assume it’s a nuclear attack, and react accordingly.
Because they *can* be used for nuclear weapons delivery
Launching an ICBM without a clearly publish test trajectory(and sometimes even with) is going to set off launch detection systems and send everyone to high alert. Since it *could* carry a nuclear weapon it gets assumed to be carrying a nuclear weapon and will earn retaliation in kind (aka nuclear weapons heading your way)
ICBMs also don’t carry huge payloads. The US Minuteman III launches 3 warheads in reentry vehicles for a total payload of only about 1000 kg total. A wayyy cheaper Tomahawk carries a 450 kg conventional payload
You want unambiguous and cost effective weapons. Surface to surface missiles and short range ballistic missiles are wayyy cheaper and wayyyyyy less likely to get nukes flying back at you
Why would you bother to send a missile intercontinentally do deliver such a relatively small payload? Each individual ICBM costs millions of dollars, your return on investment would be ridiculously low to use a whole ICBM to launch a conventional bomb across the ocean.
It would be like using a Ferrari to drive to the grocery store, except the Ferrari gets used up just so you could grab some milk and bread. If you has a single-use Ferrari, you’d make sure to bring a huge load of groceries back in one trip to get your money’s worth. Wonky analogy but hope it helps