Transport physics limit interstellar warfare

Without convenient faster-than-light travel, a generational warship may arrive under descendants who no longer accept the original mission. Cryogenic crews avoid that political drift but create long periods of physical recovery and vulnerability during approach. Even an Earth-Mars war requires the attacker to lift and deliver overwhelming resources against a defender already at the destination. Planetary occupation becomes implausible without mass-produced soldiers or a convention that orbital control compels surrender, revealing how logistics can overwhelm the familiar imagery of space war.