Some questions that might guide your argument ...

1. What is your definition of justice?
2. What type of warfare are you writing about?
3. What does a just war look like?
4. What are the alternatives?
5. What is the reason behind the war? Consider both/multiple points of view.
6. Who started the war?
7. How is the war fought?
8. Who is fighting the war? Did the people choose to fight?
9. What are the benefits? Who reaps the benefits?
10. What are the costs? Who pays the costs?
11. What is the impact of the war on those who fight? on civilians?
12. What is the outcome of the war? Do the ends justify the means?