Last night I watched an episode of Star Trek called “A Taste of Armageddon” (Season 1, Ep. 23). In it, two planets have been at war for 500 years, but they no longer send weapons to destroy each others’ cities.
Instead, a linked computer system models the attacks and determines casualties. These casualties then have 24 hours to report to a “disintegrator” to be killed. It’s clean, neat war, without the carnage.