I want to know the answer to the following question:
Who was forced to retreat back to the Pusan Peninsula due to unpreparedness?
All the background I'm provided with is that "In a postwar analysis of the unpreparedness of U.S. Army forces deployed to Korea during the summer and fall of 1950, Army Major General Floyd L. Parks stated that "Many who never lived to tell the tale had to fight the full range of ground warfare from offensive to delaying action, unit by unit, man by man ...". Is that enough to answer the question?
Answer: no