Kelne considered this, "There may be something to that," he said, "Certainly our own gear shows no signs of deteriorating here. Once you get something to the point where it's self-sustaining, it should keep right on going without further input." He frowned, "Still, mental domination tends to be a more active process. Remove or disrupt the magic, and the subject goes back to normal."
"There is one possibility, though. Given enough time and effort, people can be conditioned to be more receptive to 'suggestions' from certain quarters. Given that conditioning, all you'd need to exercise effective control would be a mental link. It wouldn't even need to be a particularly strong one, depending on the complexity of the commands, and how much they conflict with the subject's basic nature."
People might wonder how Kelne knew so much about compulsion. If he had his way, they'd go on wondering. The episode in his history that had set him researching it wasn't one of his prouder moments.
"As for the distance issue, I wouldn't count on that being a limiting factor. I can think of one way that could be gotten around without being insanely powerful, and I'm sure there are others." It seemed that 'having no idea' was a fleeting state of affairs for Kelne.