herders_and_tributary_constraints

herders_and_tributary_constraints = {
	trigger_if = {
		limit = { exists = scope:defender }
		scope:defender = {
			save_temporary_scope_as = recipient # done for is_a_herder_defender_tt
			NOR = {
				custom_tooltip = {
					text = is_a_herder_defender_tt					# herders can't fight
					government_has_flag = government_is_herder
				}
				is_tributary_of_suzerain_or_above = scope:attacker 	# can't fight your tributaries or your tributaries' tributaries
			}
			# You cannot attack your Confederation buddies tributaries
			trigger_if = {
				limit = {
					exists = suzerain
					suzerain != this
					scope:attacker = { is_confederation_member = yes }
					suzerain = { is_confederation_member = yes }
				}
				NOT = { scope:attacker.confederation = suzerain.confederation }
			}
		}
		scope:attacker = { # Tributaries cannot attack their Suzerain or Suzerain's Confederation buddies
			NOR = {
				is_tributary_of_suzerain_or_above = scope:defender 	# can't attack your own suzerain
				trigger_if = {
					limit = {
						exists = suzerain
						suzerain != this
						scope:defender = { is_confederation_member = yes }
						suzerain = { is_confederation_member = yes }
					}
					# if you have a suzerain who's part of a confederation, you may not attack any of its members
					scope:defender.confederation = suzerain.confederation
				}
			}
		}
		#Mandala Vassals shouldn't attack their Liege's Tributaries
		trigger_if = {
			limit = {
				scope:attacker = {
					is_independent_ruler = no
					liege ?= { government_has_flag = government_is_mandala }
				}
			}
			NOT = {
				scope:defender = { is_tributary_of = scope:attacker.liege }
			}
		}
	}
}

As written in game/common/scripted_triggers/00_war_and_peace_triggers.txt.