This drink was invented in the 1940s as a way to market a children’s juice to adults. Ocean Spray Cranberry Juice was founded in the 1930s and was successful at marketing its’ drink to children but the drink was not popular with adults. What better way to sell to adults than to add booze, because aside from getting a UTI not many adults drink cranberry juice.
The drink was called the Red Devil until the 1960s when the name changed to Cape Cod. The cranberry growers in Cape Cod had considerable pull within the company because the majority of the cranberry crops for Ocean Spray came from Cape Cod, Massachusetts. The growers were successful in forcing Ocean Spray to officially change the name Red Devil to Cape Cod. Nowadays everyone just calls this a Vodka-Cran, but I think the official name is prettier.