Biggest error in WWII. There were so many....too many to outline here...but here are a few.
We should never have gotten into the war in the first place. Had Americans not re-elected that fool and Stalin tool FDR, we likely would have avoided the war.
Another big mistake was the dropping to those two nasty bombs on a beaten and defenseless nation, killing innocent women, child, and old men purely to impress Stalin and the world...and thanks to Truman's terribly racist view of the Japanese.
Then the foolish island hopping campaign in Pacific, that resulted in lots of dead American boys, for nothing other than for making a name for the generals and admirals.
Add to all this the outrageous military material given to the stinking commies, while our men were not properly supplied early in the war...
Then the terrible aerial bombing of Germany and Japan, killing scores of innocents.
There are just too many mistakes.....but FDR's sycophantic adherence to assisting at all costs, histories most murderous dictator, has to be near the top.
War is always the health of the state...when will we ever learn?