This being so, it is an acknowledged fact that the Saguntines, a good many years before the time of Hannibal, placed themselves under the protection of <a class="linkToPlace" target="_blank" href="/place?placename=Rome&groupId=935&placeId=1669">Rome</a>. The surest proof of this, and one accepted by the Carthaginians themselves, is that when a civil disturbance broke out at <a class="linkToPlace" target="_blank" href="/place?placename=Saguntum&groupId=938&placeId=1673">Saguntum</a> they did not call in the mediation of the Carthaginians, although they were close at hand and already concerning themselves with Spanish matters, but that of the Romans, and with their help set right the affairs of the state. Therefore, if we take the destruction of <a class="linkToPlace" target="_blank" href="/place?placename=Saguntum&groupId=938&placeId=1673">Saguntum</a> to be the cause of the war we must allow that the Carthaginians were in the wrong in beginning the war, both in view of the treaty of Lutatius, in which it was stipulated that the allies of each should be secure from attack by the other, and in view of the convention made with Hasdrubal, by which the Carthaginians undertook not to cross the <a class="linkToPlace" target="_blank" href="/place?placename=Ebro&groupId=549&placeId=1031">Ebro</a> in arms. If, however, we take the cause of the war to have been the robbery of <a class="linkToPlace" target="_blank" href="/place?placename=Sardinia&groupId=947&placeId=1685">Sardinia</a> and the tribute then exacted, we must certainly confess that they had good reason for entering on the Hannibalic war, since having yielded only to circumstances, they now availed themselves of circumstances to be avenged on those who had injured them.
Walbank Commentary