Ok, not disagreeing, although I would argue that is still tactics and employment, but given this has always been an issue, whatever.
By doctrine I’ referring to why you have an MH in the first place. What do you understand to be the threat, what resources do you have (meaning national resources, primarily money, people, and industrial base), and how are you going use those resources in furtherance of defence policy. It’s impossible to write a usable weapon system CONOPs without doctrine.
So, for instance, when my opinion still mattered, I would remind people that the doctrinal roles of MH in Canada are below water warfare, above water warfare, and supporting air operations. This did not encompass all of the possible MH roles.
It would serve us well that when asked “what does MH do” we respond with the doctrinal roles, not some vague “extends the ship…”
As well, a firm understanding of what MH is doctrinally for gives a better understanding of why it’s needed. It’s raison d’être is to enable the ship to go in harms way with less risk to accomplish it’s assigned tasks.