What alternative did the Roman government have to turn to in order to provide support to its population?
The need to support its populace was a major factor in causing the Punic Wars with Carthage. As the Greeks before them, the Romans had established colonies throughout the Mediterranean to provide grain and other raw materials to the Empire. Sicily was a major supplier of grain to the Empire. The Roman government was expected to provide grain to those who could not afford it, and much of this demand was met with Sicilian grain. When the Carthaginians also laid claim to Sicily, the first Punic War erupted. The end result of that war was the withdrawal of Carthage from Sicily. There is some argument among historians that Rome attacked Carthage in the Third Punic War (which resulted in its destruction) in order to not only eliminate that nation as a competitor in the Mediterranean but also to have access to the grain fields of Northern Africa. After Carthage became a Roman province, North Africa supplied a substantial portion of the Roman grain harvest. Its capture by the Vandals was a substantial factor in the death knell of the Empire.