Can a Secret Keeper break their Fidelius Charm?

Question

It’s now been definitively established that Peter Pettigrew was concealing the location of the Potter family’s house in Godric’s Hollow as their Secret Keeper.

This means that the house was invisible and Unplottable to anyone who was not the Secret Keeper (Peter), inside the perimeter of the Fidelius Charm when it was cast (the Potter family themselves), or told later on by the Secret Keeper (like Bathilda Bagshot and Sirius Black, and presumably also Dumbledore). As such, if the charm was still intact, the following people should not have been able to see the house at all:

• Hagrid when he came to pick up Harry from the ruins
• the Muggles that responded to the explosion (police/firefighters/paramedics)
• the wizards and witches who enchanted the house to be a memorial invisible to Muggles
• Hermione, when she and Harry visits many years later (and all the wizards and witches who visited until then)

The fact that they could heavily implies that the Fidelius Charm itself had been broken. Why did the Fidelius Charm on the Potters' house break? asks why that might be, but the accepted answer doesn’t really give an answer, other than that the inconsistent descriptions of the Fidelius Charm makes it impossible to know.

Jeff’s answer to the same question, however, a most ingenious solution based on this quote from chapter 17, “Bathilda’s Secret”, in Deathly Hallows:

… and now his destination was in sight at last, the Fidelius Charm broken, though they did not know it yet …

The wording in that quote is not necessarily precise enough to know for sure—‘broken’ might just mean ‘overcome’ in this case—but if taken literally, it means that the Fidelius Charm itself had been broken (i.e., undone), and by Peter himself.¹ This would explain an awful lot. There’d be nothing strange about all those people who saw the Potter house throughout the years.² In fact, almost everything that is odd and bizarre about that night and the Fidelius Charm would become clear.

Normally, though, I should think that undoing a charm or spell would be the sole prerogative of the caster—not much point in protective spells, after all, if anyone can break them. If Peter was able to undo the Fidelius Charm on the Potters', either the Secret Keeper must be considered equal to the caster with this charm, or Peter himself must have been the caster.

Is there any canon confirmation, apart from the quote above, that Peter should be able to undo the Potter Fidelius? That is, either that a Secret Keeper can always undo ‘their’ Fidelius; or, alternatively, that Peter was the caster of the Potters' Fidelius?

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^{1 The alternative, that Voldemort could somehow undo a Fidelius charm once he was told the Secret, seems a bit far-fetched. Why would he even want to or bother? His goal was to kill Harry, and once Peter had given him their location, there’d be no point in actually undoing the Fidelius charm for him.}

^{2 We have to assume he broke it immediately before Voldemort went there, though; otherwise someone else would be almost certain to notice that there was suddenly an extra house in the middle of the street, and there would presumably have been a fair bit of commotion about that. Even assuming this, it’s still an open question how all the Muggles in Godric’s Hollow managed to deal with the fact that a half-ruined house suddenly just popped up out of nowhere one October night. Some large-scale memory charm work would almost have to be involved there.}

Answer 1

No. If it were possible for a Secret Keeper to break the charm, the Death Eaters would have expected Snape to do so with the charm on 12 Grimmauld Place. The tongue-tie curse prevented him from giving them the secret (or gave him an excuse not to do so) but could not have prevented him from breaking the charm entirely if it was in a Secret-Keepers power to do so, and Voldemort would surely have known as much.

As for why the charm protecting Harry's family was broken, it all depends on how the spell was constructed. Keep in mind that it protects a secret, not a person or thing, and presumably must be phrased accordingly. So far as I know there is no canon evidence on this point, but there are a number of possibilities that would explain the spell breaking, for example:

• Where are Lily, James, and Harry hiding? (After the attack, they're not in hiding any more.)

[Note: they would still be unable to leave the house without the invisibility cloak, since that wouldn't constitute "hiding".]

• Where is Lily and James's house? (After the attack, it belongs to Harry.)

On the other hand,

• Where is Potter's Cottage? (But is there any canon evidence that their cottage did actually have this name? And if they named it this themselves, is it still really the house's name after they've died?)

• Where is Number 8, Potter's Lane? (Between 7 and 9, probably, or 6 and 10 depending on the street layout; either way, it isn't exactly a secret, so probably can't be protected.)

[Note that I've chosen an address at random, since there doesn't seem to be a canon address.]

Note that the only other canon example we have of use of the Fidelius charm was to protect 12 Grimmauld Place. In this instance we actually do have a clue, the note Dumbledore used to reveal the secret to Harry:

The Headquarters of the Order of the Phoenix may be found at number twelve, Grimmauld Place, London.

It is clear that in this case at least, the secret must have been phrased along the lines of "where is the headquarters of the Order of the Phoenix" rather than "where is the Black family house" or "where is number 12, Grimmauld Place". (This can also be seen by the fact that in Deathly Hallows the Death Eaters were able to know where to go to keep a watch on the place.)

It seems reasonable to suppose that the Fidelius Charm protecting the Potters was phrased similarly.

Answer 2

Note that my following comments assume that the place is the secret, not the location of the Potter family.

Harry Johnston made some excellent points regarding the unbreakability of the Fidelius Charm. However, whether it is breakable or not, it should certainly be able to be nullified by the Secret Keeper, if he or she wishes. For instance, assuming James and Lily had lived and Voldemort had been defeated, James might well have asked Wormtail to place the following advertisement in the Daily Prophet:

Mr. and Mrs. James Potter wish the Wizarding community to know that their residence is located at Number Nine Potter Lane, Godric's Hollow.

... to borrow the fictitious address used by Harry. Theoretically, this would effectively nullify the Fidelius Charm by making the secret public knowledge.

However, please also note that, even if the Fidelius Charm were in effect, Harry would likely not be affected by it, since he "knew" where the Potter residence was from the time when he lived there as a young child, although since (at that time) Wormtail was still alive and Secret Keeper at the time, he couldn't have told Hermione (although this begs the question of whether he could have taken her there).

Additional thoughts:

1. The destruction of the Potters' home was the result of a powerful curse. Could this have broken the charm, similar to the way the use of Sectumsempra made it impossible to reattach George's ear?

2. Does the Fidelius Charm weaken with the number of people who know the secret? I.e., if Wormtail, as Secret-Keeper told enough people, would the charm have weakened to the point of breaking?

Final (editorial) thoughts:

1. I've always thought that James was rather an idiot to not make himself Secret Keeper, as Bill did with Shell Cottage. If he had done this and stayed inside the bounds of the charm, then Voldemort could not have found his family.

2. As an out-of-universe thought, the Fidelius Charm (as well as all other magic in the Potterverse) seems to work exactly the way it needs to in order to move the story along.

Answer 3

Maybe the Fidelius Charm doesn't actually render the location physically invisible, maybe it just makes it psychologically unrecognizable. For example, prior to the breaking, Voldemort would be able to go to the Potters' house, see it and know that it is a house, yet never be capable of consciously thinking "That's the Potters' house - that's what I am looking for!". He could even ask a passerby to point to the Potters'​ house, and look where that person is pointing, yet be incapable of registering that that house is the one pointed to.

From another perspective: maybe the Fidelius Charm acts sort of like the 'Somebody Else's Problem' field from "Life, the Universe, and Everything".

Answer 4

There is a simpler explanation. The charm was broken because the one who cast it, Dumbledore, broke it. His motto is "For the greater good", and for this good he created a villain whom he could use to justify pushing laws and regulations that he needed, and then the created a hero that could be used to defeat the villain.

If you don't believe me, ask yourself where did Tom Riddle learn about Horcruxes? No school literature would refer to it, but he knew to ask Professor Slughorn about it.

Why didn't the Potters hide in Hogwarts or at the headquarters of the order? Because they were bait to lure Voldemort out.

Why did Snape overhear a private teacher interview for divination position? Why would he have been there? Why did he take only a part of the prophecy to Voldemort? Because he was an agent for Dumbledore and followed his orders.

Why was Harry sent to the Dursley's? The so-called protection is something he never needed, since the Dursley's were never attacked. Even then the only time he was in danger with Dementors, they were perfectly able to attack him so if there was some protection it was on the house itself, not a very useful thing.

The simple fact is if you stop falling for the book's assurance that Dumbledore is some goody two-shoes, you will see him for the shrewd manipulator he is, he killed Grindelwald to assume the position of hero, and when he started losing influence and prestige from that he raised another villain, Tom, to fight and eventually defeat.