Why, exactly?
What could they possibly have there that they want to protect?
Their rice paddies?
A straw purchase for the ChiComs. Maybe we need P-3 control and a 30 day waiting period...
Vietnam is part of the group disputing the spratley islands on top of the Phillipines, China, I think Japan, and maybe one or two others. It would give them the ability to patrol the ocean region they claim - a capability they don’t currently have.
What's left of their offshore islands and oil and gas resources that the Chinese haven't taken yet?