Why didn't Dobby just steal the diary?

Question

Dobby's motivation in Harry Potter and the Chamber of Secrets seems to be to protect Harry at all costs from the opening of the Chamber.

"No, no, no," squeaked Dobby, shaking his head so hard his ears flapped. "Harry Potter must stay where he is safe. He is too great, too good, to lose. If Harry Potter goes back to Hogwarts, he will be in mortal danger."
"Why?" said Harry in surprise.
"There is a plot, Harry Potter. A plot to make most terrible things happen at Hogwarts School of Witchcraft and Wizardry this year," whispered Dobby, suddenly trembling all over. "Dobby has known it for months, sir. Harry Potter must not put himself in peril. He is too important, sir!"
_{(Chamber of Secrets, Chapter 2, Dobby's Warning).}

Dobby doesn't seem to have noticed that, as a half-blood, Harry wouldn't have been a prime target for the Monster of Slytherin, but maybe he didn't overhear the Malfoys going into details on that part of the plot.

Anyway, Dobby's plan for protecting Harry seems to be roughly as follows:

• Warn Harry not to go back to Hogwarts.
• Steal Harry's mail so that he thinks his friends don't want him to go back to Hogwarts.
• Try to get Harry expelled from Hogwarts by performing magic in his house.
• When Harry ignores his warning, block the entrance to Platform Nine and Three Quarters.
• When Harry gets to Hogwarts by another method, bewitch a Bludger to attack Harry so that he is sent home, "grieviously injured".
• Warn Harry again.

There are so many things which can and do go wrong with this plan, but the thing that all Dobby's schemes have in common is that they allow Lucius Malfoy to reopen the Chamber of Secrets.

Wouldn't a much simpler, less troublesome and more effective plan have gone something like this?

• Steal the Riddle diary and hide it somewhere.
• Prevent the reopening of the Chamber of Secrets.

This would be an iron-clad method of safeguarding Harry from the Malfoy plot, and would have the added benefit of also protecting the hundreds of other students and staff at Hogwarts (who Dobby doesn't seem to give a second thought for).

Of course, this would mean that Dobby would have to betray his masters - but then again he was already doing that by warning Harry. His actions throughout the book are one big continuous act of disobedience.

The key to this one is probably whether Dobby knew about the specific involvement of the diary in the Malfoy plot. If he didn't then he wouldn't know to steal it. However, Dobby certainly knew about the diary at the end of the year.

The elf was doing something very odd. His great eyes fixed meaningfully on Harry, he kept pointing at the diary, then at Mr Malfoy, and then hitting himself hard on the head with his fist.
_{(Chamber of Secrets, Chapter 18, Dobby's Reward).}

If he knew about the diary, why didn't he just steal it?

Answer 1

This is mostly speculation, but it could possibly be because it contradicts the most fundamental rule of house-elves: he is not allowed possessions. Likely as an extension of this, he is also not allowed to steal any of his master's things.

If this type of thing was allowed, then in defiance of his master he could have taken any object and squirreled it away to help Harry, or to get back at the Malfoys, such as the key to their Gringotts vault or their wands, if he were never specifically instructed not to.

Him taking the diary without being ordered to, and without giving it to someone else, would mean that he has, in essence, taken possession of it. Even if he hides it in the woods somewhere, this would probably constitute in his mind that it is now "his", which he knows he is not allowed to do.

Notice that when Dobby stops Harry's mail, he gives it over as soon as he is asked about it, probably because in his mind he was stopping it in transit and thus it was still in the process of being delivered, just very slowly. If he was stealing the letters, he would probably not carry them around all of the time, or he could even just destroy them in order to make sure Harry never gets the mail.

In addition, when Sirius is clearing out Grimmauld Place and Kreacher tries to stop him getting rid of some of the Black family possessions, he never takes them for himself and hides them somewhere they would never find to stop them being taken, he just relocates them inside the house to make it inconvenient.

He might have also been afraid of Lucius figuring out that he was aiding Harry Potter. Even if he had done what Kreacher did and just relocated the diary to make it difficult to find, he could have just been ordered to retrieve it from wherever it was in Malfoy Manor, and then they might realize that he had deliberately moved it to try to hinder them.

Answer 2

Dobby may have been directly ordered not to mess with the diary.

House-elves are magically forced to obey their master’s orders. Once Kreacher passed into Harry’s ownership (despite his desire to belong to Bellatrix instead) and Harry told him to shut up, he did shut up even though he was trying very hard not to.

“Give him an order,’ said Dumbledore. ‘If he has passed into your ownership, he will have to obey. If not, then we shall have to think of some other means of keeping him from his rightful mistress.’

‘Won’t, won’t, won’t, WON’T!’

Kreacher’s voice had risen to a scream. Harry could think of nothing to say, except, ‘Kreacher, shut up!’

It looked for a moment as though Kreacher was going to choke. He grabbed his throat, his mouth still working furiously, his eyes bulging. After a few seconds of frantic gulping, he threw himself face forwards on to the carpet (Aunt Petunia whimpered) and beat the floor with his hands and feet, giving himself over to a violent, but entirely silent, tantrum.”
_{^{- Harry Potter and the Half-Blood Prince, Chapter 3 (Will and Won’t)}}

It’s clear from what happened to Kreacher, who was perhaps even more defiant than Dobby, that house-elves are magically bound to obey their masters. All Lucius would have needed to do is tell Dobby he can’t do anything to interfere with the diary, and he’d be unable to, no matter his willingness to disobey.

There are enchantments that seem to prevent even the most willfully disobedient house-elves from saying too much of their master’s secrets.

“Can’t house-elves speak their minds about their masters, then?’ Harry asked.

‘Oh, no, sir, no,’ said Dobby, looking suddenly serious.‘’Tis part of the house-elf’s enslavement, sir. We keeps their secrets and our silence, sir, we upholds the family’s honour, and we never speaks ill of them – though Professor Dumbledore told Dobby he does not insist upon this. Professor Dumbledore said we is free to – to –”
_{^{- Harry Potter and the Goblet of Fire, Chapter 21 (The House-Elf Liberation Front)}}

This seems to be at least part of the reason why Dobby was telling Harry about everything only in hints. He would have likely gotten orders not to reveal the plot, and got around that by using hints. Harry later used Kreacher to spy on Draco, and made sure there was no way Kreacher could get around them.

“Master wants me to follow the youngest of the Malfoys?’ croaked Kreacher. ‘Master wants me to spy upon the pureblood great-nephew of my old mistress?’

‘That’s the one,’ said Harry, foreseeing a great danger and determining to prevent it immediately. ‘And you’re forbidden to tip him off, Kreacher, or to show him what you’re up to, or to talk to him at all, or to write him messages, or … or to contact him in any way. Got it?’

He thought he could see Kreacher struggling to see a loophole in the instructions he had just been given, and waited. After a moment or two, and to Harry’s great satisfaction, Kreacher bowed deeply again and said, with bitter resentment, ‘Master thinks of everything and Kreacher must obey him even though Kreacher would much rather be the servant of the Malfoy boy, oh yes …”
_{^{- Harry Potter and the Half-Blood Prince, Chapter 19 (Elf Tails)}}

Kreacher was then forced to obey Harry because he couldn’t think of any way around the orders he’d been given.

Harry was a specific target - him being half-blood didn’t matter.

Harry himself tried to convince Dobby to leave him alone by reminding him he’s not a Mudblood. However, that didn’t convince Dobby at all.

“So there is a Chamber of Secrets?’ Harry whispered. ‘And – did you say it’s been opened before? Tell me, Dobby!’ He seized the elf’s bony wrist as Dobby’s hand inched towards the water jug. ‘But I’m not Muggle-born – how can I be in danger from the Chamber?’

‘Ah, sir, ask no more, ask no more of poor Dobby,’ stammered the elf, his eyes huge in the dark. ‘Dark deeds are planned in this place, but Harry Potter must not be here when they happen. Go home, Harry Potter. Go home. Harry Potter must not meddle in this, sir, ’tis too dangerous –”
_{^{- Harry Potter and the Chamber of Secrets, Chapter 10 (The Rogue Bludger)}}

In addition to targeting Mudbloods, Harry was a specific (and perhaps even the main) target, because of his involvement in Lord Voldemort’s loss of power.

Answer 3

It seems that house-elves have limited avenues of disobedience. We can assume that if Dobby could have stolen or disposed of the diary he would have done so.

Nearly all of Dobby's acts of disobedience harm or disadvantage Harry. Something that Dobby would have known that his master would not have disapproved of.

So it seems that the restriction on what house elves can do is based on the action itself rather than the intent of the action.

Stealing the diary would have been very much something that his master would not have wanted him to do, so he is unable to do it. Jinxing a bludger to grievously harm Harry is not something his master would have disapproved of, so it seems he can get away with it, even if Dobby's intent was to save Harry.