Including the rest of that paragraph:
And yet, to become a soldier ... The other boys dreamed of joining the army, of fighting with King Gavilar. There was talk of going to war with Jah Keved, once and for all. What would it be like, to finally see some of the heroes from stories? To fight with Highprince Sadeas, or Dalinar the Blackthorn?
The Way of Kings chapter 16
This implies that the boys were daydreaming about participating in a war against Jah Keved, and there's other conversation about going to war to find a Shardblade and becoming a lighteyes.
Other than these children daydreaming, there is other mentions of skirmishes between the highprinces in order to expand their own borders. We know that the Alethi are a highly militant people who have only recently been unified by the Kholins, and before that presumably would regularly duke it out amongst themselves as well as the bordering Vorin princedoms.
There's also the possibility that any border conflict is allowed (or at least, tolerated) under any actual peace treaties between the nations, due to the relative autonomy granted to the highprinces.