What was the U.S. objective in fighting for Guadalcanal?

The U.S. objective in fighting for Guadalcanal was indeed to protect Port Moresby, as it served as a crucial forward base to attack Rabaul. Guadalcanal was strategically important because it provided a location for airfields that could support operations against Japanese positions in the Solomon Islands and ultimately enable further advances toward the Japanese stronghold at Rabaul. Control of Guadalcanal would facilitate increased air and naval operations in the region, directly supporting efforts to protect Port Moresby. This strategic positioning allowed the Allies to ensure that their supply lines and troop movements were secure, while also preparing for offensive actions against Japanese held territories in the southwest Pacific.

This focus on establishing a stronghold at Guadalcanal, to safeguard Port Moresby and enable offensive operations against Rabaul, highlights its crucial role in the broader context of the Pacific Theater during World War II.