Duckk wrote:What makes you think that compelling a surrender from orbit would result in "devastating the planet"? As Terekhov so ably demonstrated, you can drop a very precise KEW on any target you want with minimal collateral damage.
Furthermore, as mentioned by David in several posts, the common practice of warfare between civilized nations is that once the attackers control the orbitals, the planet surrenders. Resisting beyond that point is meaningless unless you're deliberately trying to inflate the body count.
Now, there could well be a few occasions where one is dealing with some truly maniacal personality who refuses to surrender even when the situation is hopeless, and the attacker chooses not to inflict casualties from bombardment. Alternatively, one is trying to attack a site which makes bombardment undesirable (for example, capturing a hardened R&D facility on a moon somewhere). In which case, yeah, you probably would call up the Army and stage an assault. But unless there aren't any non-combatants around, or were evacuated beforehand, any opposed invasion is likely going to cause casualties at least as bad as a bombardment would. That being the case, you go right back to putting orbital bombardment back on the table in order to avoid losses to your own troops. There's just no point in trying to resist if you lost the high ground.
Well, you really can't "compel" a planet to surrender from orbit. It may clearly be in the best interests of someone to surrender but you can't actually compel anything from a distance, which is sort of the point.
Yes, I'm sure you can target Kinetic Weapons very precisely but essentially all you're doing is substituting kinetic energy from chemical or nuclear energy and how much energy you need to use is still going to be governed by the target you are trying to destroy. If the target is well defended and strengthened to resist such attacks, the amount of energy needed to reduce it could be very substantial and lead to considerable collateral damage.
Essentially, if you have a structure designed to resist a nuclear explosion, then you're going to need an energy release equivalent to a nuclear explosion to engage that target effectively. While a KEW probably would be a cleaner weapon in comparison to a Nuke, that energy release is still going to damage a lot of things and kill a lot of people, probably people you'd rather not kill.
How do you deal with enemy forces in the field or dispersed throughout major urban areas without devastating the areas surrounding them? Does "precisely target" mean a hypervelocity pebble for every soldier? Do RMN ships carry dedicated mass drivers for just such an event? What would you have to do to defeat a planet which has made substantial preparations to defend against such an attack? If you are using KEW's, what would be the difference between using a weapon of mass destruction and using KEW's to subdue a planet?
Yes, granted most worlds aren't going to take this option and will choose to submit rather than face this possibility, and most planets which don't can effectively be bypassed. But there may well be situations where the aggressor force actually needs the planet itself and the planet is prepared for and chooses to resist.
KEW's have the same problem as nukes. If you really need to depend on them to force a planet to surrender, you really need the planet to either cooperate with you or you need to be prepared to devastate it's surface otherwise the threat that goes along with it's use is relatively minor, sort of like lobbing the occasional cruise missile at people you don't like. People need to believe you will use them as WMD's in order for them to be cowed into submission.