Why didn't Vader kill Sidious before ANH?

I've always wondered why Vader didn't turn on Sidious before ANH. In ROTS Anakin tells Padme that he can overthrow the Chancellor. So why didn't he? I can't believe he was content being Sidious' apprentice for so many years in between episodes III and IV. I mean, Anakin always had such high aspirations of being the most powerful Jedi ever. Why would he remain a servant of Sidious? Even Sidious admitted to Yoda in ROTS that Vader would be more powerful than either of them.

 

He had no reason to. In ROTS he wants to overthrow Sidious so he can rule the galaxy with Padme; after she's dead that plan obviously goes out the window. Then there is a twenty year gap where Vader is just a lonely, angry bad guy...until he finds out he has a son. Then he wants to overthrow Sidious so he can rule the galaxy with Luke.

 

Between the trilogies, he is basically forcing himself to become the monster that he turned himself into. He has no real reason to kill Palpatine. He ruined his life by becoming his apprentice and it's almost a self-punishment to remain living for so long under Palpatine's power.

 

In my view: Because he couldn't. For one thing, he lost a lot of his power due to his Mustafar-confrontation, but what's more important, there wasn't anyone for whom he had a passion to risk his life (and to risk his life, an attempt to kill Sidious would certainly have been). All he did, Anakin did for a person special to him: His mom, his wife, Obi-Wan, Palpatine. Never for abstract ideals. Only in ROTJ, there was a reason, an emotional reason for him to kill the Emperor - namely his son's imminent death. And, as I posted elsewhere, he did it by mere human power - no extraordinary midichlorian counts, no superior Force skills, no army he needed. Simply throwing him down the shaft was how he killed Palpatine.

Edit: Perhaps the most part of his power he didn't lose due to his injuries, but due to the fact that he had lost everyone who had ever meant anything to him.

 

He had no apprentice ready to take Sidious' place. Once he learned of Luke's existence, he wanted to take Luke as an apprentice and overthrow Sidious.

 

Are you serious that he wants to rule the universe with Padme? He does, afterall, know her, and she is a staunch republican (in the Star Wars sense of the word) and has absolutely zero interest in ruling the world with Anakin or anyone else. He just says that to try to justify his unjustifyable position. Really he just says this because Lucas can't write, this is terrible dialog, but either way, I think it can be disregarded. He just wants to rule the galaxy anyway he can; so if there was ever an opportunity he would take it. I think the original question is a good one.

 

Because Palpatine would simply shock his controls and he'd be dead. He needed someone with no handicap to throw overthrow Palpatine - namely, Luke.

And like that...he's gone.

 

I have to disagree with that. While many things can be held against Anakin, he didn't seek power for power's sake. He had a motive, and that motive was people who were close to him. Maybe he couldn't realize that Padme wouldn't go with him, maybe he just didn't want to realize. The point, to me, is: He wanted the power for Padme's sake. Not just for the sake of power. That's the difference betweeen Palpatine and him.

 

When Palpatine made that statement regarding Anakin's potential, that was before he (Anakin) was injured, which lessened his potential.

Vader didn't kill Palpatine because he couldn't. He needed someone powerful to help him, and until Luke came into the picture, no one fit the bill.

 

Mandragora, I think the difference between Palpatine and Anakin is that Palpatine has reached a point in his dark side confidence that he no longer needs to lie to himself. Anakin has not reached this point. Clearly his love for Padme is merely an excuse by the time he mentions ruling the galaxy with her. It is not clear that she would put Anakin before her republican values, rather she would choose to die, which she does. Real love tends to be symmetrical.

 

Darth Poppy, I completely agree that Padme would never have given in to a - however benevolent - dictatorship. But that's how WE perceive it. Anakin, for certain, would disagree. I think he just didn't want to see and accept this. Additionally, I agree with you that he is lying to himself - but I think I disagree about the reasons why he lied to himself. I just don't see him merely as a ruthless, power-lusty would-be emperor. In my opinion, there has always been a - however ill-fated and mislead - desire to protect the ones close to him in him.

Edit: I would also concede that this desire was mainly motivated by his fear to lose these ones that are close to him.

 

I can't see the connection between Anakin's injury in ROTS and his inability to destroy Palpatine. The ability of an individual to use the force has never been associated with that individual's physical attributes. With the Vader suit, he's still quite capable of being a great swordsman with a lightsaber and his knowledge of the force itself wouldn't diminish. I would assume after a few years Anakin would be accustomed to the armor and mechanical limbs and it wouldn't be an issue anymore. But even still, the physical makeup doesn't have much to do with the person's force capabilities. Just take Yoda for example. He was one of the strongest force users of all time, but was physically very limited.

 

As usual, Ousley is correct. His plan had become taboo, and he had no reason to kill Sidious and become Emperor. Power meant nothing to him anymore.

 

You don't know the power of the dark side. I must obey my master.

A delightfully ambiguous line (that unfortunately was not explained in the PT). I don't understand why that is so, but that is the reason.

 

I'm sure Anakin would've loved to kill Palpatine, but he simply couldn't. He's lost his limbs, meaning he can't throw or repel Sith lightning. Killing Palpatine would mean losing his own life, which is what happens in ROTJ.