

Your fleet will immediately deploy its entire manpower stock to the surface and a ground battle will begin. Once a system's defenses have been sieged down to your liking, use the Invasion action while your fleet is in orbit to start a ground battle. This may or may not be useful depending on the faction you're playing, but it could make them cheaper to field. ℹ️ Note that, unlike many modules, it's legal to equip siege modules on civilian ships, like colony ships. If that's all they have, they'll end up near enough to zero to immediately give you a "Decisive Victory", and prevent the trench warfare from ruining the system. However - if you first siege the system down to zero manpower, the number of troops raised by "Draft" is something that a reasonably modern/upgraded assault force can often kill outright in a single turn, especially with a Blitz strategy.

Any attempts to turn up the heat with more aggressive battle tactics only make the destruction worse, as the system depopulates and loses buildings. On each turn, a defender can issue a "Draft" strategy, and replenish enough manpower to keep on fighting, turn after turn (potentially for a few dozen turns).

The second reason is that the developers mindfully set up the numbers so that sieging can be used to opt out of a "death spiral" that frequently happens when assaulting a system the enemy truly does not want to lose. killing populations or system improvements), unlike most types of invasion strategies. The first reason for this is that sieging, itself, does no "collateral damage" whilst in progress (i.e.
