Your sides don't want annihilation. They want victory.

Smashing the other side's planets is not victory. It's like going to steal a prized racehorse and killing it during the theft. You want the planets, as the thief wants the horse. That's the entire point of war.

Destroying planets would occasionally, perhaps, be necessary, but you don't want it. Conquest of other planets is, in fact, the only way to recover from the economic damage of going to war.

Plus, MAD can work either if other civilizations are out there, and all agree that a planet-buster requires all powers to unite against that one, or if the people of your own civilization think that busting planets is proof of insanity, and if your own underlings don't overthrow you, you (and the underlings) will be torn to pieces by the enraged mobs.

Also, MAD have its own political and military risk when you are not the only one having the planet buster. This is just like why Russia haven't use nuclear weapon on the first day of war.

Your sides don't want annihilation. They want victory.

Smashing the other side's planets is not victory. It's like going to steal a prized racehorse and killing it during the theft. You want the planets, as the thief wants the horse. That's the entire point of war.

Destroying planets would occasionally, perhaps, be necessary, but you don't want it. Conquest of other planets is, in fact, the only way to recover from the economic damage of going to war.

Plus, MAD can work either if other civilizations are out there, and all agree that a planet-buster requires all powers to unite against that one, or if the people of your own civilization think that busting planets is proof of insanity, and if your own underlings don't overthrow you, you (and the underlings) will be torn to pieces by the enraged mobs.

Your sides don't want annihilation. They want victory.

Smashing the other side's planets is not victory. It's like going to steal a prized racehorse and killing it during the theft. You want the planets, as the thief wants the horse. That's the entire point of war.

Destroying planets would occasionally, perhaps, be necessary, but you don't want it. Conquest of other planets is, in fact, the only way to recover from the economic damage of going to war.

Plus, MAD can work either if other civilizations are out there, and all agree that a planet-buster requires all powers to unite against that one, or if the people of your own civilization think that busting planets is proof of insanity, and if your own underlings don't overthrow you, you (and the underlings) will be torn to pieces by the enraged mobs.

Your sides don't want annihilation. They want victory.

Smashing the other side's planets is not victory. It's like going to steal a prized racehorse and killing it during the theft. You want the planets, as the thief wants the horse. That's the entire point of war.

Destroying planets would occasionally, perhaps, be necessary, but you don't want it. Conquest of other planets is, in fact, the only way to recover from the economic damage of going to war.

Plus, MAD can work either if other civilizations are out there, and all agree that a planet-buster requires all powers to unite against that one, or if the people of your own civilization think that busting planets is proof of insanity, and if your own underlings don't overthrow you, you (and the underlings) will be torn to pieces by the enraged mobs.

Also, MAD have its own political and military risk when you are not the only one having the planet buster. This is just like why Russia haven't use nuclear weapon on the first day of war.