Harry Dresden - what impact breaking his word had on his power?

Question

It was mentioned first in "Grave Peril":

"Poor little poppet. All of your efforts to learn and you still know so little. Harry made a bargain with me long ago - and broke it, once then, and once a few nights past. He swore to uphold it again, last night, and broke it thrice. Now he reaps the consequences of his actions. His own powers turn against him, the poor dear, to encourage him to fulfill his word, to keep his promise."

So question is: when he broke his word, what were the effects on him? In Grave Peril, during Bianca's party, he basically became powerless when just meeting Lea there, but there must have been more. Bargains made there and later saw him get it back, but question is: since his first broken bargain with Lea was his power reduced and how?

Was it reducing his output (that is making him weaker)? Or was it siphoning some of his power to Lea? After all the oaths were on his power, so it's not unreasonable to think it was some sort of security on his oath (a lien of sorts)? Was it all the time or just in Nevernever, where Lea had power to exact the payment of the debt?

Or maybe it was just a reminder of his "treachery" - sort of like being pestered by bank: not really bad thing (yet), but annoying to the extreme?

When later Ms Sommerset paid him a visit his debt was a factor, yet it was our world, not Faerie... And still later, when he renegotiated, did his power - if he had parted with any - retuned to him?

As time passes Harry is getting better with magic, more precise, so it would definitely align with his recognition that he was more economical with it, but was it only that? Was being frugal with power (which is not surprising - he is part Scottish, after all) the only explanation for him getting better and stronger? Or maybe he got back what he lost (if he lost anything)?

Answer 1

Dresden didn't lose any magic by breaking his word. His magic, instead of bending to his will, started working against him. Whatever mystic forces that dictate the laws of magic deemed him untrustworthy, but his power is still his. Dresden actually stated at least once in one of the books (I don't have a quote in front of me) that that is precisely why wizards need to take their word more seriously than normal humans- they have more power to work against them when they break their word.

The magic system in the Dresden Files is pretty consistent, and Dresden approaches many aspects of his art with near scientific processes and explanations, but it isn't science. The arcane and seemingly fickle rules are sometimes hard to predict even by the mightiest wizard, which is why Dresden didn't plan on getting the use of his power back when he renegotiated with Lea on the bridge. He just needed to get where he was going in a hurry without the Fae stopping him.

His word (and his power) is already restored well before Mab shows up in disguise in the fourth book, so the Queen buying his 'mortgage' doesn't have any influence on his power by that point.