Leadership in a coalition war of logistics

Who was the most influential single person in the Second World War apart from the major national leaders?

It is hard to isolate one person: the officers coordinating Allied logistics and convoys mattered as a collective system.

Coordinating convoys, goods, and resources across several theatres was too large a job to reduce neatly to one individual. Major wars are managed through interconnected institutions as well as famous commanders. Eisenhower, Cunningham, Nimitz, and others can be proposed, but none acted independently of a worldwide coalition system. Logistics coordination itself becomes a decisive form of leadership. Kings and Roman emperors illustrate the same problem: a ruler personally leading one front cannot simultaneously coordinate the resources and decisions needed across several theatres.