Which command relationship involves placing units in a relatively permanent organization that controls them primarily?

The command relationship that involves placing units in a relatively permanent organization that primarily controls them is referred to as "Assign." When a unit is assigned to a command, it becomes part of that command's organization for a considerable period of time. This relationship typically indicates that the assigned unit operates under the command's direction and is integrated into its larger operational structure, ensuring coordinated planning and execution of missions.

In this context, assignment is a structured approach that facilitates deeper integration and resource management between the units and their higher commands. This is different from relationships like attachment, where a unit is temporarily placed under the control of another unit without the same level of integration or permanency. Similarly, organic units refer to forces that are inherently part of a higher unit structure and do not involve the reallocation of units, while tasking involves the delegation of specific missions without the same degree of control inherent in assignment.