This is the other thing to remember - the Jedi Order as we know it from most of the media is the tail end of thousands of years of existence, and decline. That’s even a major plot point in the Prequel Trilogy - the Jedi are having trouble seeing the future. They’ve become ossified, more concerned with ritual than substance. Quite a lot of what they “know” about the Force is received wisdom. They believe it because that’s what they were taught by their teachers, who believed it because that’s what they were taught by their teachers, yadda yadda yadda. Most Jedi have never even met a Sith, or other Dark Force User, let alone fought one. Qui-gon running into Darth Maul was a huge surprise to them all, and even then, they weren’t sure what exactly Maul was.
Quite a lot of what they taught and believed was probably bullshit, which is why Yoda ended up burning all those books.
Yoda himself had been a Jedi for something like 750 years at the time of Phantom Menace. Surely he would have remembered how things were in the old days. Maybe he was just in denial as well, thinking the bad times would never return, or maybe the Jedi teachings had already become corrupted even as far back as when Yoda was just Baby Yoda .
This. Personally, I think the Jedi were wrong from the very beginning. Otherwise they wouldn’t have ever needed a Chosen One to bring “balance.” The Jedi would have been a lot stronger and together if they’d allowed their members to get laid and maybe have a family.
Yeah, such long-lived characters are always a problem in such stories. Of course, the history goes back several thousand years, so to Yoda, this is like someone in their 80s, who remembers the Korean War and maybe WWII, being asked about the Civil War, or the War of the Roses, or the Punic Wars. “Beats the shit out of me, man, that’s from way before my time!”
It’s too bad Tarkin got killed when the Death Star blew up. He was the only one who could ever get Vader to stop force-choking annoying guys in staff meetings.
The ending of ROTJ bothered me for a long time when I was a kid, because I couldn’t quite follow the chain of reasoning. If, to be a good Jedi, Luke had to toss away his lightsaber and not go through with finishing off his opponent, it left me with the burning question, “How does a Jedi ever win a fight?” That puzzled my young brain for quite some time.
Looking at it now, I tend to agree that the whole, “Once you start down the dark path, forever will it dominate your destiny” thing was crap, or at least an oversimplification. It’s true in general that evil is seductive, and breaking the rules is often easier than abiding by them.
But the Jedi’s fear leads to anger leads to hate bit is too simplistic, and seems to go against human nature. It’s not really possible to not feel fear, and in many cases fear is a valuable survival tool. Maybe that’s why the Bene Gesserit emphasized confronting and controlling fear (“I will face my fear. I will permit it to pass over me and through me.”) rather than declaring that you should never experience it at all.
So no, I don’t think that Luke would have instantly fallen to the Dark Side had he killed Palpatine. Anakin had several years worth of festering, barely-suppressed rage and hatred when he turned, which Luke had simply never experienced.
And it’s not just him being “unsure” of himself that makes the difference. In the Prequels, Anakin is still trying to be a Jedi. He tries to control his anger, even if he fails occasionally. What makes him into Vader is that he stops trying to stop himself. Anakin portrayed a struggle with the Dark Side, Vader just rolls with it. So Vader doesn’t (often) look or act angry, because he doesn’t have to be angry for very long. You annoy him, he kills you, he moves on. No struggle.
I viewed the path to the dark side from an addiction model. It’s easy and seductive. Palpatine’s hope is that Luke uses the dark side to defeat Vader, and Luke becomes addicted to the power of the dark side. It’s not that he can’t go back to the light (as Vader shows), but rather, why would he, this is so easy and so powerful.
Being angry, afraid, and full of hate leaves you more vulnerable to the lure of the dark side. Your will check to resist is more difficult if your emotions aren’t under control.
I like to remember that the force gives its users a bit of precognition, so Palpatine, a more powerful force user than Luke or Vader, know that the blow is coming ahead of time. If necessary, Palpatine can start reacting before Luke starts. He also knows Vader is reacting to parry the blow, so Palpatine does not take any action.
I know some of this is talked about in the movie, but it seems that Palpatine is taking a big risk sending Vader after Luke:
Vader kills Luke, a big threat is eliminated
Luke kills Vader, a big chance that causes Luke to turn, and Palpatine gains an even more powerful apprentice
Vader turns Luke, and they team up to kill Palpatine, because there can only ever be two
Recall that this story is not about humans. Ultimately the human Lucas is selling the story to late 20th Century humans so the creatures in the show have to have some behavioral similarity to humans for the show to be comprehendible and for the appropriate characters to be perceived as heros and villains in the conventional tropes of human drama.
But just as the MCU can have characters of superhuman strength, speed, etc., the intelligent humanoids of the SWU need not be perfectly human. In their ability to learn to channel the Force they have some capabilities that no human has. Why could they not also have, at least potentially, better control of their fear and other emotions than we do?
Certainly the Shaolin monks and and other ascetic human sects have very different ideas about self control than an overweight pizza-and-soda addicted 25yo playing vid games all day in Mom’s basement in Kansas City has. And that’s just humans, not getting into fictional humanoids.
If, falling back to the OP’s title, all we take into account is the Original Trilogy, then yes, I think we can say that it’s plausible that Vader and Palpatine felt that unleashing his hate would cause a fall. Everything we’ve seen of Luke in the OT shows a very impulsive, very emotional young man (and with reason!) who could very easily fall down the expedient path.
It is arguably the death of Ben and the counsel of his force ghost, as well as the strong examples of his friends (especially Leia) in being cool, effective leaders that tempers him. But even Yoda in TESB points out his weakness, and the images he sees in the Dark Force Cave show that externally or internally (depending on how you take what happens) he needs to be aware of it himself. It’s a part of that imagery, and the shared loss of humanity in comparisons in their missing hands in ROTJ that helps pull Luke back.
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Having said all that, if we go past the OT, there’s reams and reams of previously canonical works (the various games and expanded universe stuff that has been unequally re-affirmed) that has tons of redeemed Jedi who recover after falling to the dark side, including Luke. Granting that Palpatine is a master of Sith Alchemy as well as a powerful force user, it strikes me as plausible that given any opening in Luke’s moral structure, Palpatine could use it as a wedge to control him.
Much of the expanded universe has Luke trying to complete his own training and recovering Jedi traditions lost to the purge and time itself. That thirst for knowledge and training is his downfall (temporary in most cases) in a lot of those stories.
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