This was building even from the first movie, when he was afraid of being on his own without his mother. He was a good kid, but he let his fear rule him. That's not to say that it's *wrong* for a young child to be afraid of being separated from their parents. It's quite normal. But with a child who has "phenomenal cosmic power", maybe it's not so cool.
In the second movie....he was conflicted....he was powerful, and chafing at the bit, but the other Jedi kept pulling him back, not trusting him. He experienced strong emotions, but from what I saw, the way that Obi-Wan tried to manage them, by cutting him down, was not the right way to handle that type of person. All it would do is cause resentment, which is exactly what happened....and exactly what Hayden Christensen portrayed in the second movie. Which is kind of funny, because that's what people *complained* about in them movie. In actuality, he was doing exactly what he was supposed to do.
The Jedi didn't trust him. And yes, because of his power, and immaturity, they had reason to act that way. But by treating him like a child, they made the situation worse.
Then his mother died. He couldn't stop it, nobody did anything to help her....and he felt horrible for having abandoned her to a horrible death. And he snapped. Could happen. Except that instead of pulling out a gun and shooting people he had a lightsaber and "phenomenal cosmic power" and butchered an entire tribe of sand people. And because nobody knew about it, they couldn't help him deal with it.
And, finally, in the third movie, he experiences fears of his wife dying. It's already established that he can't deal with loss. He said in the second movie that he would find a way to keep people from dying. A noble goal, but one that leaves us asking.....just how far would he go to keep someone from dying? Pushing himself to the limit? That could be noble. Killing other people to keep another alive? Not so noble..
The council didn't trust him. Especially because of his relationship with Palpatine. They knew he wasn't completely emotionally stable. And his power was growing so quickly that they were probably afraid of giving him a position of power.....because though he had massive powers, he didn't have the wisdom yet to temper their use. But instead of managing it properly, they didn't really explain why they were doing what they were doing. Even when Mace went to confront Palpatine, he just told Anakin to follow orders...but didn't explain *why* those orders were being given. It was like a slap in the face to someone with Anakin's abilities and pride. It showed a fundamental lack of understanding of how to manage people, IMO.
On the other hand, the Emperor was all nice, and gradually began inserting doubts as to the Jedi path. He showed a path that he claimed could save Padme. He made it seem that the Jedi's reticence to teach Anakin everything they knew, because they didn't trust him, might cost his wife her life.
So, Anakin made his choice. I think he was on the knife's edge for a long time. Finally, Palpatine showed him an alternate path, and it met his goals of saving his wife.
Once he made the choice, I believe that cognitive dissonance could have taken care of the rest. He made a decision, and took action which flew contrary to his core beliefs (ie. joining the Dark Side). Because he made that decision, and there wasn't an immediate and tangible reward, he actually adjusted his core beliefs to justify the actions he was now taking. This likely made it easier to take the actions he did.
I suspect the Force had a lot to do with it at all. I think that the Force, light side or dark side, has a way of feeding on and magnifying emotions....more importantly, it gives a powerful means of acting on those emotions.....that's why Jedi teachings said that they had to control their emotions. Think of how paralyzing fear can be. It can make someone freeze even as they are about to be shot, or run over or whatever...even when action could lead to their survival. Or anger.....anger can make people who have loved each other for years say hurtful things to each other than they'd never say in an ordinary day. And that's normal people. Now imagine having phenomenal cosmic power. If someone had that kind of ability, and hadn't been able to master their emotions, then their emotions could take control of them, and they could then enforce a solution on the world around them. I think that's partly what happened to Anakin. If he didn't have a belief that there was a possibility of saving Padme through his abilities, I would be willing to bet he wouldn't have turned.
Anakin was troubled, and taken from his mother after he'd bonded with her, and put in an emotionally "cold" environment, where he may not have received the warmth he was used to receiving. In her absence, this affected his further development. The Jedi didn't have the means of teaching him what he needed to learn, since they were usually trained from an earlier age, where children could be moulded to avoid some of these problems.
It's an incredibly sad story, in a lot of ways. And I don't think that it's an entirely unbelievable character progression. It took 3 movies to get to where Anakin turned. All the movies showed were pivotal events in that development.
Banshee
