Why did armies protect their lines of communication during siege warfare?

In the context of 18th-century siege warfare, armies prioritized the protection of their lines of communication—the vital routes connecting a force to its bases of operations and supplies—because these paths were essential for sustaining the elaborate logistics required to conduct a siege.12

During this era, warfare became increasingly formalized and sluggish, characterized by the use of magazines—strategically located, prestocked depots established to support besieging forces. Because these armies relied heavily on these depots for food, equipment, and ammunition, their security became a primary strategic concern. Commanders often deployed entire armies to defend these routes against enemy interference. Consequently, military campaigns frequently devolved into maneuvers aimed at threatening or defending these critical bases and supply lines, as generals recognized that the most effective way to defeat an opponent was to starve them by severing their access to necessary resources.2