What type of drink is a Moscow Mule primarily classified as?

A Moscow Mule is primarily classified as a highball because it typically consists of a spirit, in this case vodka, combined with a larger proportion of a non-alcoholic mixer, which is ginger beer, and is served over ice in a tall glass, often a copper mug. The key characteristics of a highball include this distinction of having a base spirit mixed with a carbonated beverage or other mixers, served in a generous quantity. The refreshing nature and balanced flavor profile of the Moscow Mule align with the highball category, which usually emphasizes a light and easy-to-drink quality.

While it can be considered a mixed drink due to the combination of ingredients, "highball" more specifically captures its serving style and flavor integration, which is essential for categorization.