Declaring War in Stellaris currently requires you to have a Casus Belli. Casus Belli translates to “provocation of war” in Latin. This permits you to press the vital “Declare War” button. Casus Belli comes in a variety of forms. They vary from claiming a region to humiliating your opponents.
How to Win a War Guide in Stellaris
After you declare war, the defending Empire is allowed one year (in game time) to set their War Goals. These War Goals can influence the likelihood of an opposing side surrendering or agree to a truce on your terms.
They also determine the victory or loss conditions of war. This guide will teach you more details about War Goals and what you need to do to improve your chances of winning in Stellaris.
Winning a War
Once you press the “Declare War” button you will need to set a War Goal to determine the winning and losing conditions. To be victorious, you will need to meet these requirements.
There are currently four existing War Goals and these are: Conquer, Humiliate, MakeTributary, and Vassalize. When you wage war, your opponent will have a negative modifier.
You must gather enough points to cancel out the negative modifier for them to surrender. The maximum number of points you can earn will be 250:
Maximum of 100 points for War Fatigue
Maximum of 100 points from occupying their land
Maximum of 50 points if your fleet’s power is greater than theirs