"as always the true power in a relationship is from the subordinate party, they can always say no"

That's the first I've heard of this line of thought. Is there research on this statement? It's pretty counter-intuitive to think that the true power in a relationship lies with the subordinate party. I don't see how slaves, military personnel, or even office workers could be considered truly powerful over their superiors. In some cases saying "no" would lead to serious inconvenience and possible misery. In other cases it could lead to death.