The thing with wars: the more you have and the longer they take, the more acceptable they become for everyone, especially for the ones seeking to start the next one.
Unfortunately is a good time for wars.
Discussion
It's mostly the US that wants war though and they are biting off more than they can chew these days.
When you get to rule the world you need good teeth. The next ones to rule it will have to do the same to stay at the top, chew everything they can.