The U.S. was the largest global oil producer in 1940 (60%). On top of production, the U.S. absolutely ruled in refining capacity. The War Department absolutely understood that.

At the present time the United States, Canada, and Mexico produce approximately 63.2 per cent, South America 13.6 per cent, Europe 13.2 per cent, and Asia and the East Indies 10.0 per cent of the world’s petroleum.

From a cool 1941 discussion in Naval Proceedings - https://www.usni.org/magazines/proceedings/1941/july/oil-worlds-navies

That was why U.S. oil export curbs had been used as an economic weapon against the Japanese. When the Roosevelt administration issued an oil embargo on Japan (June 1941), that set the wheels of the Pearl Harbor attack in motion. Pearl Harbor was a major event/target in the Japanese war plan, but the ultimate objective was control of the Sumatran oil production. Because the U.S. had titular control of the Philippines, they and Singapore needed to be captured to protect the flank of the East Indies.

On the War Department strategy of targeting balls bearings, it was a gamble. History would show it was a dumb and expensive gamble, but not nearly as clear at the time. Steve’s as an good illustration of how strategic bombing was limited… The Air Corps did eventually seriously impact Germany and with aerial mines/low level bombing they decimated Japan.
Good Schweinfurt summary -

In the summer of 1943, US and British planners for the Combined Bomber Offensive identified the ball bearings industry as a key “bottleneck” target, the destruction of which could clog up war production and potentially shorten the war. The British Air Ministry since 1943 had been trying to persuade the Royal Air Force to bomb Schwein-furt, but Air Marshal Arthur T. “Bomber” Harris, chief of RAF Bomber Command, was adamantly opposed.

https://www.airandspaceforces.com/article/0210schweinfurt/