code:

	trigger = {
		ai = yes
		NOT = { local_flag = USADefense }
		OR = {
			war = { country = USA country = CAN }
			war = { country = USA country = MEX }
			AND = {
				lost_national = { country = CAN value = 2 }
				NOT = { war = { country = USA country = CAN } }
			}
			AND = {
				lost_national = { country = MEX value = 2 }
				NOT = { war = { country = USA country = MEX } }
			}
			AND = {
				lost_national = { country = USA value = 2 }
				atwar = USA
			}
		}
	}