CIMSEC has published a two part discussion of planning for Maritime Security Operations written by retired US Coast Guard Captain Andrew Norris.
Much of the discussion is about the inadequacies of the current planning guidance. It picks up in Part 2 with a discussion of the “Constraint-Restraint-Enabler-Imperative (C-R-E-I) Model.”
While written as guidance for the planner, it might also serve as a checklist for the operator, as he prepares execute Maritime Security Operation. Have constraints, restraints, enablers, and imperatives been identified and are they adequately understood? Has training in these consideration been adequate? Do I have everything I need to implement and exploit the enablers?
Chuck Hill's CG Blog 
I do not understand all the jargon. What does it mean in simple language.