system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] Do Sith lose any power after turning to the light?

Let’s say Luke managed to save Darth Vader and turn him to the light. Vader makes a full recovery from throwing Palps down the reactor hole.

Is Vader still as powerful as he was when he was a Sith or does he lose that power after turning to the light?
gpt
>"Is the Dark Side stronger?"

>"No, no, no. Quicker, easier, more seductive. Not stronger."

-Yoda and Luke

Your question is really a matter of what you mean by "power". A lot of people tend to look at the Force as a tool or weapon. While this is understandable in certain contexts, the true power of the force is the enlightenment one attains by becoming in tune with it. An example of this is the dichotomy between typical light and dark side users. The Jedi Knights were "the guardians of peace and justice in the Old Republic" for millenia, and while the Jedi certainly developed widespread doctrinal issues towards the end of the Order's life, for the vast majority of their history they lived up to these ideals. There were hundreds of them, deployed across the galaxy as negotiators, peacemakers, and investigators, fighting to protect the common people of the Republic. They used the Force to gain insight into the lives of those around them, and to detect hidden motivations and plots. Contrast this with the Sith. There were many Sith orders, and all of them were characterized by infighting, betrayal, and mistrust. With a few notable exceptions, the vast majority of the Sith are purely combat-focused, and use the Force for offense: killing and assassinating their foes to attain more power over others. Light Side users view this as a perversion of the Force and an abuse of the power granted by it.

So that said, when a Sith like Vader turns back to the light, they voluntarily give up a lot of what made them "powerful" in the eyes of others. If they are not used to fighting without Dark Side force powers, they will probably lose raw combat ability as well. But the trade-off is that they begin to heal themselves and their relationships with the people around them. For the first point, the Dark Side feeds off your negative emotions: fear, anger, hate, envy, and distrust. The Light Side feeds off of inner peace and serenity. It should be obvious which is healthier for your mental state in the long run. And for the second point, Sith don't have friends. They have tools, primarily, maybe temporary allies. Even the relationship of Master and Apprentice between Sith is often seen to be abusive and manipulative, and tainted by the knowledge that one will some day kill the other. In contrast, Jedi do have friends, and often can't achieve their full potential without them. Luke doesn't blow up the Death Star without Han and Chewie taking the TIE fighters off his tail. Revan doesn't redeem himself and save the Republic without Bastila and the crew of the Ebon Hawk. And as contentious as this scene is, even Obi Wan doesn't find Kamino and Jango Fett without Dexter Jettster and his crazy 50s diner. A Sith might have the edge over a Jedi one-on-one (Although this is absolutely not a guarantee), but a Jedi backed up by their friends and allies wins every time. Is that more powerful than being able to shoot lightning from your hands or choke someone with your mind? You decide.

**Edited to add:** This is actually what makes Sidious's plan so genius. He doesn't go after the Jedi one by one, or blow up the Temple in one huge attack. He doesn't start his own Sith Empire to fight them, like so many of his predecessors. Instead, he takes away what makes them Jedi. They become peacekeepers forced to fight a war, their mastery over their emotions tested daily by constant death, destruction, and combat. They lose the support of the common people, and the support of the Senate, and when the end comes, even their relationship with the clones under their command is undermined and taken away. It is a total defeat, only reversed when Luke's self-sacrifice and love for his friends inspires Anakin to finally take up his mantle as the Chosen One and destroy the Sith to save his son's life.