Final answer:
The statement is false. According to just war theory, a war can only be morally justifiable if it is declared and overseen by a legitimate authority.
Step-by-step explanation:
The statement that a war does not have to be sanctioned by a legitimate authority is one of the criteria used in judging whether or not a specific war might be morally justifiable is false.
In just war theory, the concept of a legitimate authority is a key element in determining the morality of a war. According to this theory, a war can only be morally justifiable if it is declared and overseen by a legitimate authority, such as a recognized government or international organization. This ensures that the decision to go to war is made through proper channels and is subject to accountable governance.