Domination Magic: Dark Side of the Force

This is the first installment of a series on my (incomplete) thoughts concerning magic used to dominate other people.

Caveat: I am not knowledgeable about the Star Wars Expanded Universe. My questions here—to myself—may have been answered there. I am unbothered by that.

“You don’t know the power of the Dark Side. I must obey my master.” — Darth Vader, Return of the Jedi (1983)

That line has fascinated me for decades. How much control does Emperor Palpatine have over Vader via the Force? Not total, as Sith apprentices frequently kill their masters. As to why not, total control would result in a mere puppet rather than the needed junior partner and successor. So partial control of some kind. Magical control. Something beyond the mundane tools of social control which might be ineffective against special subordinates. Enough to keep the subordinate in line without losing what makes them special.

This could simply be a magical analogue to physical coercion: causing pain to the target’s mind instead of their body until the desired behavior is performed. That analogue is sufficient but neither interesting nor creative.

But the important detail is the partial domination. Almost none at all, judging by the frequently successful rebellions.