To comment on the idea that war is always imminent in Through the Looking-Glass, go through Lewis Carroll’s novel and find the places that continually indicate the threat of war. However, this could prove to be a futile exercise. While soldiers make a brief appearance in chapter 7, the tale tends to lack normative markers of war, like guns and bombs.
Maybe war is being used in a different way. Sometimes, war carries a less literal meaning; it may refer to general conflict, aggravation, or upset. There is a lot of that in Through the Looking-Glass. It seems like wherever Alice goes, confrontation is nearby.
For instance, when Alice ends up on the train, sure enough, quarrel and discord—war—ensues. The Guard scolds her for not possessing a ticket. The other passengers then join and criticize her for various reasons. They suggest that she should have to pull the train the rest of the way.
Alice, in a sense, contributes to the war-like spirit of the novel because she doesn’t yield to the denizens of her dreamworld. She stands up for herself. In the scene with the train, she refuses to give into the passenger’s demands. She won't pull the train.
Besides spats and quarrels, it’s possible to argue that war is always imminent because, as in war, the creatures in Through the Looking-Glass are perpetually in a precarious state. They’re susceptible to a number of transmogrifications, including, in the case of the Bread-and-Butterfly, death.