Question

What was the purpose of the Office of War Mobilization?

Answer 1

OWM was in charge of coordinating all government agencies in the war effort, WWII. The director held so much power that he was sometimes called "assistant president."

Anyone who values individual liberty and freedom would be aghast at how far reaching this and near absolute power this unelected appointee held. But it was war time and the people generally supported kicking Axis butt. So it worked out. It helped the FDR died and Truman closed down shop on the OWM.
There is a reason the 22nd amendment was proposed and ratified quickly after FDR's death. An executive who reigns 12 or more years can gather a lot of power to himself,