What a Pacific-first American strategy would change

How would the war change if Roosevelt chose the Pacific before Europe?

Nimitz would probably have greater influence, but no faster Pacific victory is expected because shipbuilding and deployment limits remain.

In this counterfactual, Pacific priority probably gives Nimitz a still larger role, while the consequences for MacArthur remain an open question. The explanation for Europe-first places particular weight on Germany's perceived ability to develop atomic weapons. Most US naval strength was already committed against Japan, so the main allocation decision concerned the Army and Army Air Forces. Europe would still receive some support, with fighters suggested as one contribution. Britain, North Africa, and the Mediterranean offered places to assemble forces and gain experience as the American army expanded. Pacific distances and limited opportunities to deploy forces would leave additional units waiting for transport and support. The stated conclusion is that changing priorities would not accelerate the war against Japan, because American shipbuilding could not be pushed faster.