Jar Jar Binks
The Significant Mistake: As Junior Representative in the Galactic Senate, it was the gormless Gungan who granted Senator Palpatine emergency powers to use his clone army to fight Count Dooku's Separatists. Worse, it's just about his only scene in Attack of the Clones.
Impact On The Saga: Jar Jar's vote made the Clone Wars possible. Y'know; two TV series, one spin-off film... Oh, and the small matter of Palpatine getting one step closer to becoming Emperor.
If The Force Had Been Strong With Him: It's hard to criticise Jar Jar for this, given that he shouldn't have been placed within 100 light years of anything approaching a position of responsibility. But like so many others, he apparently can't tell from the sneering voice and malevolent stare that Palpatine's a bad'un.
The Significant Mistake: The whole trip to Cloud City is, in retrospect, a major ball-drop. Not only does he get himself frozen in Carbonite and Leia imprisoned, but the knowledge of what's going on causes Luke to abandon his training before he's ready.
Impact On The Saga: The whole detour to Jabba's palace might have been avoided and they could have got on with stopping the Empire in time for tea.
If The Force Had Been Strong With Him: C'mon, he's Han Solo. He must have hundreds of hide-outs. Let's be charitable and assume that Cloud City was the only one where he didn't have a love rival to Leia stashed away.
Grand Moff Tarkin
The Significant Mistake: Blessed with a moveable killer planet, Tarkin bizarrely parks it around the curve of Yavin waiting for the Rebel moon to orbit into view before obliterating it. We're not buying any gubbins about gravity. Tarkin's grandstanding, pure and simple.
Impact On The Saga: The small matter of giving the Rebels time to mass their forces, launch an attack and - oops - blow up the Death Star with Tarkin on board.
If The Force Had Been Strong With Him: Throttle down, hit the accelerator, fly that sucker into a firing position.
The Significant Mistake: Amazingly, the same one as Jar Jar, although in her defence she makes it first. Not only does she fail to see through Palpatine, she initiates the Vote of No Confidence in Senate leader Finis Valorum that allows Darth Sidious to rise to power.
Impact On The Saga: The usual - Sith, war, Empire. With added personal baggage that Palpatine persuades her hubby to become a genocidal arsehole.
If The Force Had Been Strong With Her: She'd have refused Palpatine as Valorum's replacement. After all, she's a Queen, she can do what the hell she likes.
The Significant Mistake: In a word, monologuing. A bounty hunter who has caught the prime catch of his career doesn't stop for a chat, especially not at a cantina table where your would-be victim's hands can prepare a blaster.
Impact On The Saga: Luke and Ben would be stuck on Tatooine, or at least have to try and find another vaguely honest pilot in Mos Eisley. Good luck with that.
If The Force Had Been Strong With Him: Follow Han out of the cantina and shoot him in the back on the street. Easy, if unsporting.
Star Destroyer Captain
The Significant Mistake: On being told an escape pod is fleeing the Rebel ship, the captain decides to hold fire because "there are no life forms." He comes to this conclusion despite the prevalence of droids in the Star Wars universe, or the fact that the Death Star plans everybody's after aren't alive anyway.
Impact On The Saga: This is the big'un. Blow up the pod, no R2. No R2, Luke stays a farmboy, doesn't meet Obi-Wan, doesn't rescue Leia, doesn't destroy the Death Star. And Star Wars would be the most expensive short ever filmed.
If The Force Had Been Strong With Him: He'd have done it for the sheer fun of it. Surely the whole point of becoming a Star Destroyer Captain is to blow shit up?
The Significant Mistake: Is there anything he actually does right? He can't control Anakin; then he chooses to hide his son on a) Dad's home planet and b) using the same surname; and finally he spends several decades sitting in a cave doing bugger-all. (See also: Yoda.)
Impact On The Saga: A completely baffling delay in his doing anything about stopping the Empire. Frankly, it was good luck that R2D2 landed on exactly the right planet first time, otherwise Kenobi would still be counting grains of sand.
If The Force Had Been Strong With Him: He'd have adopted Luke as his own son, and trained him as a Jedi from birth.
The Significant Mistake: Betting against Anakin Skywalker. OK, it seemed a safe bet opting for a known cheat instead...but what price failure, when Anakin is his best mechanic?
Impact On The Saga: Anakin would have stayed on Tatooine fixing landspeeders, so no Vader, no Luke, no saga. Ironically, though, he wouldn't have been around to fight in the Battle of Naboo, so Palpatine might have become Emperor quicker, Vader or not.
If The Force Had Been Strong With Him: A spread bet on the number of crashes in the podrace. He'd have made a fortune, and got to keep Anakin to boot.
The Significant Mistake: Not throwing in Anakin's mum in the bet he made with Watto. Yeah, the slave trader drives a hard bargain... but Qui's a Jedi.
Impact On The Saga: Anakin might have stayed sane with his mom around to stop him being a petulant brat. He certainly wouldn't have gone loco avenging her murder at the hands of Tuskan Raiders.
If The Force Had Been Strong With Him: A side-bet with Watto on C-3PO saying something pedantic and unhelpful.
Jabba The Hutt
The Significant Mistake: Mistaking revenge for bling. After all, hanging a frozen Han Solo on your wall like it's a carbonite portrait is bound to attract thieves. Or, in this case, Han's Jedi mate.
Impact On The Saga: Han lives on to lead the Rebel recce to Endor. And Jabba's gangsta's paradise lies in ruins.
If The Force Had Been Strong With Him: Tighter security at least. R2D2, Lando and Leia were all able to infiltrate his lair incognito to get the plan started before Luke even shows up.
The Significant Mistake: Speaking of daft things going on at Jabba's palace, what's Boba Fett doing hanging around there anyway? Typical bounty hunter: he's gonna blow his fee on booze and women, and Jabba will end up getting his cash back.
Impact On The Saga: In narrative terms, very little. In movie terms, the decline of an ice-cool, enigmatic figure into a gangster's groupie destined to be eaten by a giant sand vagina with teeth.
If The Force Had Been Strong With Him: He'd have scarpered to survive into his own spin-off franchise.
Endor base commander
The Significant Mistake: Not checking the CCTV properly before opening the front gate. C'mon fellas, Trojan horse. Oldest trick in the book.
Impact On The Saga: The shield would have stayed up, Lando would be toast and the Death Star 2 would have remained intact.
If The Force Had Been Strong With Him: He'd have called the driver of the walker's bluff, and told him to enter the pass code to get back into the bunker.
The Significant Mistake: The sneaky Nemoidian is a walking disaster zone throughout the prequels, spectacularly failing to complete any of the assassinations he's behind.
Impact On The Saga: A very one-sided contest for Palpatine and his allies. Instead, surviving a Nute Gunray-sanctioned hit is a rite of passage towards becoming a thorn in the future Emperor's side.
If The Force Had Been Strong With Him: He'd at least have noticed the double meaning when Darth Sidious tells him that he's sending Vader to "take care" of him. Nute, that's hitman talk, mate. I'd leg it if I was you.
The Significant Mistake: Having worked tirelessly to stop Darth Vader finding the location of the Rebel base, she then flies straight there in the Millennium Falcon despite suspecting they might be tracked.
Impact On The Saga: Fortunately, Jedi-in-waiting Luke and last-gasp comeback kid Han are around to save her bacon, but the tangible result is a lot of dead Rebels and a seriously depleted X-Wing fleet.
If The Force Had Been Strong With Her: She'd have led the Death Star on a wild goose chase until it ran out of petrol.
The Significant Mistake: Even a bad-ass like Vader has his off day. The decision to attack the Rebels with a lumbering convoy of AT-AT Walkers suggests a man putting coolness before practicality.
Impact On The Saga: The Rebels have time to escape, regroup and defeat. The AT-ATs have to go back to the shop.
If The Force Had Been Strong With Him: Ice skates on the AT-ATs, maybe?
Stormtroopers (all of 'em)
The Significant Mistake: Not training harder at target practice. Given that even Obi-Wan Kenobi thinks they have a reputation for precision, standards must seriously have fallen since his day.
Impact On The Saga: Just one shot on target, and the whole thing is over.
If The Force Had Been Strong With Them: They'd be able to shoot with their eyes closed, like Luke can.
The Significant Mistake: Not trusting his instincts. Having initially vetoed the decision to train Anakin as a Jedi, he lets his colleagues sway his opinion. Bad manager, he is.
Impact On The Saga: A peeved Anakin would probably have turned evil anyway. However, without Jedi training, he'd be a rubbish baddie.
If The Force Had Been Strong With Him: He'd have launched a can of whup-ass on the Council for not listening to him.
The Significant Mistake: The Luke obsession. Back in prequel days, he was quite happy to slaughter every last Jedi. So why he's suddenly so insistent on 'turning' young Skywalker to the Dark Side?
Impact On The Saga: A fatal tangle with a father/son tag-team. (Moot point: does Anakin intervene because he's after redemption, or because he thinks Palpatine's trying to replace him with a new apprentice?)
If The Force Had Been Strong With Him: He'd have killed both Skywalkers and taken on Boba Fett as a new Dark Lord.
The Significant Mistake: Although he's yet another person who failed to spot Palpatine and Anakin's deception, his inclusion here is for doing something far more significant: killing Jango Fett.
Impact On The Saga: To be fair, son Boba probably would have gone into the family business anyway. But it's the personal trauma that makes him such a danger.
If The Force Had Been Strong With Him: He'd have hunted down Boba and decapitated him, too. PG rating be damned.
The Significant Mistake: Kissing Leia.
Impact On The Saga: It so nearly sent things spinning into a whole new world of wrong, given that she's his twin sister. Good job somebody told them.
If The Force Had Been Strong With Him: He'd have able to play the field a little more.