The limits of an American embargo against allies

Would the United States embargo allies who were preventing communism from gaining a foothold in the Caribbean?

An actual blockade is considered unlikely; an embargo remains possible, although trade across the Atlantic and back would complicate it.

A blockade is considered unlikely in this hypothetical dispute with allies active against communism in the Caribbean. An embargo remains a possibility. Goods moving across the Atlantic and back would make such restrictions harder to enforce. The particular countries and measures are unspecified in the surviving question.