The theme of this is that all the parties involved in the war have to suffer great losses even if they win the war.
Step-by-step explanation:
The theme of I sing the battle which has been written by harry Kemp is a theme which inspires a lot of people and make people feel for the people who are involved in the war.
The theme of this is that when the parties are involved in a war, there is a party which wins and there is one who loses the war but one thing that is true for both the parties is that both of them have to suffer great losses either in the form of property or life.