S4: How did the enemy exploit sustainment weaknesses to contribute to the US withdrawal to the Pusan Perimeter?
The enemy exploited shortcomings in recognized materiel solutions to problem sets identified during WWII, e.g. tanks and anti-tank weapons, then outpaced the ROK and American efforts to reinforce key points with troops, weapons, and all classes of supply. Troops were unable to affect the oncoming enemy armor formations with man portable weapons, artillery pieces with anti-armor capabilities were limited in ammunition so as to be ineffectual, and what man-portable anti-infantry weapons that were on hand were so short on ammunition that long term defenses were ineffectual and eventually overrun. ROK units had minimal access to armor and what was available was unsustainable in the face of oncoming nKPA formations. In short: The wrong kind of bullets and not enough of them.