Supply deliveries that change history

What single supply delivery, or failure to deliver, had the greatest effect on history?

Congo uranium for the Manhattan Project is a leading candidate, but Malta relief shows the wider strategic importance of supply.

Congo uranium for the Manhattan Project is offered as one candidate, while Malta relief offers another measure of strategic impact. The wider lesson is that war is normally about moving and denying supplies. Atomic-bomb components carried by Indianapolis and the breaking of major sieges provide other scales for measuring a delivery's effect. The closing discussion broadens that lesson to small procedural failures: compromised Enigma material and predictable message openings could create leverage far beyond an individual mistake. The exchange deliberately avoids a single definitive answer because logistics and operational security shape wars through many linked actions.