Key Figure in European Theater Strategy

In the context of World War II, the United States implemented various strategies to gain an advantage against Axis powers. One of the critical debates among U.S. military leaders was regarding the priority of different theaters of war. In 1943, a decision was made to focus resources on the European theater before fully committing to a campaign in the Pacific. This decision was shaped by several factors, including the perceived immediate threat posed by Nazi Germany, the level of aid provided to Britain, and strategic discussions among Allied leaders. In terms of military planning, this choice had profound implications for operations in both theaters. Which key figure in U.S. military leadership was most influential in directing this focus on the European theater during strategic discussions in 1943?