It consists of my understanding of the rules as written, plus some alterations of my own. The former section contains one deadly statement which appears to contradict much in the latter. Ignore this statement. What follows is based on the assumption that it doesn't apply. All other rules for MUs are valid.
Command determines the ability of units and MUs to operate effectively.
In order for a MU and its Leader to move in unison, they all must be In Command. In the following schematic charts, the red levels are In Command, and the green are Out of Command. Two Command Points are available. In the above example, all levels are In Command. This time, the Corps Leader is Out of Command.