War is so costly because it requires reciprocal action and therefore wasteful escalation. The force that drives this is the need to “win”. This is the same force that ruins politics.
If you can accept some of what you want, maybe even in a context of getting mostly what you don’t want, but this avoids conflict because you’ve given up the need to win, then you save yourself from having to pay the costs of conflict. Most of the time this is a good deal.
To guard against war you have to call out people trying to win for winning’s sake. You have to contextualize all dispute in their concretes. You have to quantify grievances first, before thinking about conflict second. Even Clausewitz hoped for this.
But war and politics in America is a system of winning because otherwise the other guy will win. So let’s kill each other.