US Naval Bases and Ports

[kalos72]

So the consensus seems to be private/civilian security or perhaps Marines?

Reason I ask is I am trying to understand the New London/Groton drama in TheLastSubmarine and they note that the "Marines and sailors reinforced the front gate", seeming to imply that there was a Marine detachment there at least. Yet I cant find anything about marine security detachments being used as port security.

I dont want to expose any security risks or anything just trying to figure out how the military would reinforce important naval bases and ports in time of war.