What was the first offensive operation involving Marines in World War II?

The first offensive operation involving Marines in World War II was Guadalcanal. This campaign began in August 1942 and marked a pivotal moment in the Pacific Theater. The battle of Guadalcanal was significant for several reasons; it was not only the first major land offensive by Allied forces against Japan, but it also aimed at securing the island and the surrounding waters to protect the supply lines and maintain a foothold that could be used for further operations.

The successful seizure of Guadalcanal provided the Allies with an essential base for subsequent operations and initiated a series of offensives that would eventually lead to the liberation of occupied territories in the Pacific. The campaign showcased the Marine Corps' ability to conduct amphibious assaults and highlighted the importance of combined arms operations, including air support and naval bombardment in conjunction with ground forces. This operation set a precedent for future Marine engagements and established the credibility of the United States military in prolonged engagements in the Pacific Theater.