Alliances with at least 2 systems may declare war on each other.
While alliances are in a state of war the following apply.
Attacks above 50% landsize ratio
gain 10% resources.
Attacks below 50% landsize
ratio gain 10%.
Minimum landgrab is 20 land.
Missiles do full damage.
There is no limit to raids per day.
Generals will attack against overwhelming odds.
Your generals are anxious to go out again,
so they return from the attack faster.