DMH said:
Or how do nations in typical D&D settings survive such an onslaught of magic?
Now that there are high level people who can cast such powerful spells running around, why aren't they tapped to obliterate cities and farmlands of opposing nations? Even if they are forced into a fight by a similar group, the impact of such a battle is going to be horrendous and possibly lethal for lots of low level bystanders. What happens to a nation when their commoner peoples are killed en masse? At what power level does MAD come into effect?
1. You rarely want to obliterate cities and you never want to obliterate the farmland unless you're crazy or things have gone from 'war' to 'genocide'. You never want to kill the cities or croplands because you're going to want them for yourself.
2. Many wizards that get to those levels don't have much to do with normal people like kings and such. They could care less about wars and who happens to be baron today: they're trying to unlock the secrets of the universe.
3. They have to know those spells. All wizards don't have access to all the spells. That further cuts down on the available war wizard pool.
4. MAD virtually never comes into effect: wizards generally tend to cancel each other out. You cast
Control Weather. The other side
Controls it back to the way it was. No matter what spell they're using, the other side can always Counterspell it or Dispell it or use some antimagic device or spell to block/destroy the spell effect.
5. Assassins. There hasn't been a wizard made yet that can work a spell with a dagger between his ribs.
6. There are not a lot of mass destruction spells that cover a large area. In fact, I can't think of a single one that would be useful on a city-sized target. Nothing covers the area or range needed to use spells in that manner save for Control Weather and that by itself does no damage at all to things in it's area of effect unless you get really lucky and get a tornado. I think Control Weather is one of those 'last sentence' spells; it says 'possible' weather rather than 'you can summon tornadoes at will'. It's also easily dealt with if the other side has Control Weather as well. At best it would make things bad for the other wise, but those things will be equally as bad for your side as well. A tremendous thunderstorm would probably keep the opposing side from sallying forth, but that's about it.
7. Even a 20th level Wizard only has a few of those prepared at any one time (we're going on the assumption here that not every - nor even most - Wizard has a 26 Int by the time they're 20th level - PC's are the ones that tend to put everything they have into one stat - so they're going to have, like, 6 spells of any level available to them) . A 20th level sorcerer has more but it's unlikely they'll go for the really huge effect spells. They maybe can blow down a wall or a gate but that's about as much as they're going to get. Plus they have to be in range to do that, and it's very likely that some kid on the wall with Far Shot and a Comp Long Bow is going to put a war arrow in Mr. Mage's forehead before he gets off more than a couple spells of that maginitude. It's likely that he'll lose spells to blown Concentration checks. People are going to respond like PC's in one respect: if they see someone casting, they're going to instantly do their best to peg him.