Why didn't Voldemort use the Unbreakable Vow with his Death Eaters?

Question

The "Unbreakable Vow" is a charm that forces you to do something or die.

Well then, why didn't Voldemort use it with his Death Eaters to guarantee their loyalty?

Had Voldemort used it, his Death Eaters would have spent their days (after his incident with baby Harry) doing their best to find Voldemort, instead of hiding or pretending they were being controlled by the Imperius Curse.

Of course, it is possible that Voldemort did use it with some of them, but they really thought that Voldemort was truly gone forever, so the charm was pointless since Voldemort seemed to have gone. But I still think he didn't use the charm, because, as a minimum, he would have used it with Snape. And Snape undoubtly betrayed him.

Now then, maybe the charm can only be done once? Some kind of restriction? I don't remember any reference about that though...

Answer 1

One thing you must remember is that Big V was in it for himself. He was not willing to give others any form of power over him, and he was quick to promise power, wealth, etc to his underlings to gain their support, and threaten them to guarantee it.

As DVK said, the vows also had to be specific - Snape vowed to do specific actions. It's certainly reasonable to assume that vows have to be specific.

It's also reasonable that an intelligent underling, if promised something for his service, would make that part of the Vow. "I will do as you have commanded, and be rewarded as you have promised," or similar. The Vow would then bind both parties - and Voldemort was not one to easily surrender his freedom.

Voldemort is also smart enough to know that a clever subordinate or opponent might try to trick him into breaking a Vow, if they learned of it. I don't know if his Horcruxes would have let him survive breaking the Vow, but losing his body sure did inconvenience him. It's likely he'd be very leery of giving anyone power over his physical form, no matter how tenuous.

Answer 2

I don't know of any canon reason, but presumably he couldn't foresee any of his underlings being brave enough to risk his wrath by betraying him, and overestimated his abilities as Legilimence.

Also, the vow seemed to need to be fairly specific - not "you won't betray me"

Answer 3

The Unbreakable Vow precludes good surprises, not just bad surprises.

Voldemort was willing to admit — not just to himself, but publicly — that he could make mistakes, such as when time ran out on his ultimatum to Harry during the Battle of Hogwarts:

"I thought he would come," said Voldemort in his high, clear voice, his eyes on the leaping flames. "I expected him to come."

[snip]

"I was, it seems ... mistaken," said Voldemort.

— Deathly Hallows, chapter 34

This recognition of his limits may have kept Voldemort from using the Unbreakable Vow.

For example, Voldemort was initially angry when Snape did not immediately break cover to answer the summons of the Dark Mark, but Voldemort's anger soon turned to satisfaction at retaining a spy in Dumbledore's inner circle.¹ If the Death Eaters had made the Unbreakable Vow to return immediately, Snape would not have been able to take independent action in Voldemort's best interests.²

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¹ The summons happened at the end of Goblet of Fire, and Snape referred to Voldemort's reaction in Half-Blood Prince, chapter 2.

² Of course, that wasn't the end of the story...

Answer 4

Voldemort wants more than power - he wants a world order.

I believe this says something about Voldemort's personality, as well as his goal as a leader. To him, racial purity and the extermination of those who oppose him aren't simply personal goals; he believes it to be the right thing to pursue, and he likes to think that his supporters follow not only his power, but also his vision of the future.

In other words, he isn't looking for unwilling slaves. He may not be looking for partners in power, but he is looking for people who genuinely believe in his vision. He may hate those he wants to exterminate, but he certainly does not hate those he wants on his side. In that light, it would make sense that he would want them to participate in his war willingly - even at a somewhat increased risk of betrayal.

Answer 5

They would not have agreed to it

Voldemort controlled his followers through a variety of factors: fear, a cult of personality, and the promise of power—power in the Ministry, power over non-magical people, the power to kill without consequence. People did not join him because he told them to join or die: they joined because he promised to give things to them. Oh, he certainly had an attitude that abandoning him was tantamount to betrayal and punishable by death, but that was not the pitch.

If Voldemort had started asking his followers for vows of complete loyalty, particularly if it had become known that he was doing so—much as the Dark Mark became known outside his circle—he would likely have faced many of his followers abandoning him, and have been hard-pressed to get more. Except for perhaps two people, his followers joined him in large part because they wanted things for themselves more than they cared about others. Would they have agreed to have a constant death threat hanging over their head if that were the starting offer? Probably not.

Answer 6

I think it could be argued based on what we see in the book that Voldemort is not satisfied to see his subjects die when they fail. He gives them plenty of chances, and when they fail, and when the traitors reveal themselves... he likes to punish them before killing them.

I say this in addition to the answers above about the nature of the vows.

Answer 7

Like others said, Voldemort would not give his followers power over him. A Unbreakable Vow makes both parties equally responsible. Especially if the Vow was an exchange. (You give me your loyalty and I'll give you fame/fortune/power). Also the Unbreakable Vow requires another person to bind the two subjects. That is an awful lot of power given to someone over Voldemort. A Unbreakable Vow is a call for help. That is NOT Voldemort at all. He would never ask for help. Our one example of the Unbreakable Vow was Narcissa going to Snape FOR HELP. She feared Draco would not be able to complete his mission.

People either followed Voldemort because they believed in his ideology or feared for their lives. People would rather try to hide or run than fight Voldemort. He did not see any of his followers as strong enough to stand a chance in killing him. It's well documented the only person Voldemort feared was Dumbledore. Dumbledore was the only wizard powerful enough to survive a duel with him. Probably because he had the elder wand. We also do not know if the Unbreakable Vow is still active if one of the people die. Once Voldemort died then people wouldn't fear instant death renouncing him and not staying loyal.

Voldemort was also an arrogant leader. He rightfully thought no one would be brave enough to betray him. Snape was a loyal follower all the way up to when he found out Voldemort was going after Lily. Snape didn't betray Voldemort out of bravery but out of love for Lily and the fear of losing her. Regulus Black betrayed Voldemort because he treated Kreacher so badly. Regulus knew he would be dead before Voldemort found out about his betrayal so he didn't fear his retribution. During his first reign Voldemort did not foresee that love is more powerful than fear so he never considered it.

Also Voldemort only brought pure blood wizards and witches in his Death Eater ranks who were closest to him. They either were his schoolmates, other pure bloods from the Sacred 28 list of pure blood families, or proved their uses and loyalty in other ways like Snape being a spy inside Hogwarts. He had a lot more followers but those people and creatures did not have a close connection or any valuable information on Voldemort.

Answer 8

If the Dark Lord made an Unbreakable Vow, he’d risk his own life.

To make an Unbreakable Vow, both people involved put their lives at risk, since if either one who made the Vow breaks it, they will die as a result of their breaking the Vow.

“Well, you can’t break an Unbreakable Vow …’

‘I’d worked that much out for myself, funnily enough. What happens if you break it, then?’

‘You die,’ said Ron simply.”
_{^{- Harry Potter and the Half-Blood Prince, Chapter 16 (A Very Frosty Christmas)}}

The Dark Lord wouldn’t want to do something that could possibly risk his own life to ensure that his followers are loyal, even if the risk was fairly low. He’d rather ensure their loyalty with threats and promises - he wouldn’t stake his own life to do it. In the choice between risking his followers being disloyal and taking any risk to his life, the Dark Lord would choose to risk his Death Eaters’ loyalty. He’s worked around their disloyalty before, he wouldn’t see it as worth risking his life over. Though he probably wouldn’t actually die because of the Horcruxes, he wouldn’t want to risk that he’d be ripped from his body and have to recreate one because he’s in spirit form, either.

Answer 9

First, it would bind him and once they were making it, he would be helpless. Secondly, he knew if he wasn’t really specific, they might be able to worm their way out. Third, he probably did with some. Fourth, he had too much faith in their loyalty and fear of him. Fifth, he had too many followers for that. Sixth, he had, ah, other means of keeping people in line ( like the imperious curse and the Inferi).