system
Given the following post, respond as if you're commenting on Reddit:
human
[Interplanetary] Is there any way to explain interplanetary warfare without starships?

The game "Interplanetary" is an artillery game wherein the populated planets of a solar system start engaging in all-out war, without actually possessing space travel.  Or at least, good enough space travel for ships to relevant in war or successfully invade planets.  So they start firing massive railguns at each other (Think "Stonehenge" in Ace Combat), and later nuclear strikes, giant death lasers, etc.

These planets appear to be engaged in the most extreme form of total war imaginable, with lore entries alluding to school field trips in armored school buses, building road tunnels to serve as improvised shelters, game upgrades like "mandatory fertility medications," and in-game radio-astronomy telescopes to try to spot targets on opposing planets.

It seems completely insane, and yet fascinating.  Are there any circumstances where this could make some kind of sense?  It seems like if you had this tech and resources you'd just be able to do asteroid redirects (it's a late game superweapon).  And why are there multiple inhabited planets in a system that all suddenly decided they want to kill each other?  If it's to take the resources, there doesn't seem to be a way to properly exploit it from other planets even if they won.
gpt
Multiple inhabited planets are able to detect the existence of the others as they develop technological. By the time they develop any form of two way communication (radio) centuries of fears and suspicions have left them predisposed to attacking first (in a get them before they get us first kind of deal). This mean that everyone is busy investing in ways to strike the enemy as quickly as possible while the longer term fields of rocketry struggle on in the background.