However, they had to protect the shipping lanes in order to get their treasure home, and this meant keeping hold of as much of the Caribbean (or the  Spanish Main,  as it was then known) as possible.
Shipping lanes had no protection and never will.
mnli hypothesis: Shipping lanes had no protection and never will. premise: However, they had to protect the shipping lanes in order to get their treasure home, and this meant keeping hold of as much of the Caribbean (or the  Spanish Main,  as it was then known) as possible.