Clyde Shelton (Gerard Butler) is a talented engineer and family man whose life is ruined when two thugs break into his house, which results in the death of his wife and child in front of his very eyes.When the thug who commits the murders gets off with what amounts to a slap on the wrist by testifying against his less guilty accomplice (who gets put to death), Shelton initiates an increasingly elaborate plot to destroy the justice system.The prosecutor who made the agreement with the thug is the main target of Shelton, so he has to find a way to stop him before it is too late.
This film provides examples of:
Abandoned Warehouse: Clyde liquidates his assets and buys a large number of abandoned factories so he can carry out his plans undisturbed.
Adult Fear: Having your home being invaded is bad, and crippling you is worse, but the ultimate nightmare is when he rapes and murders your wife and daughter in front of you. Then, a killer gets off with a light sentence just to make sure that the justice department can get the other guy.
And I Must Scream: Darby is injected with a paralysing neurotoxin so he'll be helpless but fully conscious when Clyde cuts his limbs off. To ensure he doesn't black out from the pain, Clyde injects him with adrenaline as well.
An Arm and a Leg: Clyde cuts off Darby's fingers, his limbs, his penis, and then finishes him off by removing his head.
Badass Boast: "I'm gonna pull the whole thing down. I'm gonna bring the whole fuckin' diseased, corrupt temple down on your head. It's gonna be biblical."
Earlier, "And if we don't?" "Then I kill everyone."
Backwards-Firing Gun: When Darby realises the 'police officer' is Clyde he pulls the trigger on the Glock he took off his gunbelt. The Glock is not only unloaded, but pulling the trigger releases needles in the grip injecting Darby with a paralysing neurotoxin.
Black and Gray Morality: Let's see. He's a Well-Intentioned Extremist, willing to kill anyone to make his rather simplistic political statements. They're the forces of justice, who start out incompetent and unable to put away the bad guys, and wind up violating civil rights at the drop of a hat and staging vigilante executions.
Blatant Lies: Despite the Title Drop by Clyde, the only citizens never shown violating the law are the somewhat minor characters who get killed for making a crappy bargain that Clyde understandably feels is a mockery of justice.
Buried Alive: Darby's defense attorney is buried with oxygen and IV feed till a specific time; Nick is eight minutes late getting there and he dies.
Counting Bullets: Darby empties his revolver at the police cars pulling up at his door. As he's escaping across the rooftops, the mysterious voice on the phone tells him to wipe the gun for prints and toss it.
Disproportionate Retribution: This film could have been called Disproportionate Retribution: The Movie. Clyde Shelton's (Gerard Butler) wife and child are murdered and the prosecutor Nick Rice (Jamie Foxx) cuts a deal against Clyde's wishes, the result of which is that the accomplice gets the chair while the man who actually committed the murders gets to walk. Ten years later, Clyde wreaks revenge (including a bonus punishment for the already condemned man), then sets about destroying the entire US legal system, leaving Nick alive so that he can witness the devastating consequences of a difficult, justifiable decision he made 10 years ago. He also kills a lot of peoplewho had little to nothing to do with the deal, including Nick's assistant.
Do You Trust Me?: Nick asks this of Clyde, before revealing that he's already made a plea bargain with his family's killer.
External Combustion: Clyde plants remote-control car bombs inside the gas tanks, where a search won't find them. The protagonist is Forced to Watch as the woman he mentored struggles to escape from a vehicle with sabotaged locks as the other cars explode one by one, before her car also blows up.
Forced to Watch: Darby to Shelton, although he probably wasn't intending it.
Shelton actually ends up to doing this to Darby with himself, by suspending a mirror over him while's he's tortured, and cutting off his eyelids so he can't close them. Nick also has to watch his friends die in the car attacks, especially Sarah who's locked in her car waiting for it to explode, which it does.
Forgot About His Powers: Clyde — ordinary suburban homeowner, described as "a tinkerer", but turns out to be a genius in defence and violence whose abilities border on the fantastic. But he didn't bother to protect his own home from an intruder with a baseball bat. And why? Because he works best when he has prep time, not when he's surprised by said thug.
Gambit Roulette: Clyde is at times just impossibly good at guessing exactly what everyone is going to do.
Whether intentionally or not, It's basically a movie about a Super Villain who suffered great personal tragedy and is now trying to bring down the justice system that failed him. There's no superheroes, no setpieces, and his plan ultimately fails thanks to Nick figuring the last bomb's location out. And he only was able to do that because Clyde accidentally killed Nick's assistant, whose boyfriend happened to have access to the right information, but wasn't willing to risk his job. Until his girlfriend, ostensibly just a woman who got Stuffed into the Fridge, was killed by Clyde.
Though it's not explicitly noted, Nick's assistant is just one of several people who are blown up by Clyde. The only reason she can be considered Stuffed into the Fridge is because she got a name and character development.
Harmful to Minors: Rice's daughter puts on what she thinks is a DVD of her ballet recital, but it's actually a DVD of Shelton torturing Darby to death.
Hoist by His Own Petard: Clyde is warned not to remotely activate his last bomb. He does so anyway, only to realize it was moved to under his seat.
Hollywood Law: Ames must have had one bad defense attorney if he's put to death purely on the say-so of his partner, on the question of which one of them was a murderer, a partner who is implied to have a much longer and nastier criminal record to boot. Apparently he never thought to call the husband as a witness either. And the prosecution are the only ones who even remotely care about his opinion as well, and still dismiss it.
The reason he's sentenced and his partner is effectively let off is a piece of evidence was contaminated by a CSU during the investigation, and all the admissible evidence is suppressed under Fruit of the Poisonous Tree doctrine. The problem with this is, Fruit of the Poisnous Tree only applies to evidence collected through rights violations, and more often than not it only applies to any confession made by the defendant. A piece of evidence contaminated during investigation of the crimescene isn't applicable.
Hypocritical Humor: Nick keeps leaving his cell phone on while in court with a certain judge. While in a meeting with her later, her cell rings, and he calls her on it. Turns out there's a bomb in the phone.
Idiot Ball: Clyde's non-confession would have been harder to pull off if Nick had announced something along the lines of "For the record, he just nodded his head".
I Have a Family: Subverted. Darby is about to execute the police officer whose car he stole. The man says, "What about my wife, my little girl? I'll never see them again!" Darby is unimpressed...until he realises the cop is Clyde in disguise.
Officer: You know why I won't see my wife and little girl again? [takes off disguise to reveal himself as Clyde] Because you took them from me.
Ironic Echo: Clyde deliberately repeats Darby's catch phrase just before dismembering him alive.
Another one to Nick, "It's not what you know it's what you can prove in court"
It's Personal: Once Nick's understudy is killed, Nick is ready to go to war to take Clyde down.
I Was Never Here: The CIA assassin who meets with Nick and Cantrell opens by saying that this meeting isn't taking place. Also when Nick sees the final email sent to Sarah by her mysterious boyfriend, the email says, "I never sent this".
Joker Immunity: A major point of the movie - the legal system is tied up in tons of red tape and thus no matter what they do they can't get rid of Shelton or even move him somewhere secure, so he is continually able to commit murders with relative impunity.
Karmic Death: Darby gets dismembered alive by Shelton, who recites the same line that Darby did before he committed the murders.
One judge scolds Nick repeatedly for not turning off his cell phone. She was killed by a bomb in her cell phone, which she hypocritically answered during a meeting with Nick.
Karma Houdini: Nick can be seen as this as his desire to have a spotless conviction record was very likely the push that drove Shelton into madness and thus indirectly responsible for all the deaths including the innocent ones but gets to walk away unharmed when people far less guilty died.
Laser-Guided Karma: Less than 10 seconds after displaying flagrant contempt for duty, the rules and even the Constitution itself a bomb goes off directly in the judge's ear.
Luxury Prison Suite: Clyde insists a special mattress and a porterhouse steak be placed in his cell in exchange for his confession. The other inmates all shout with rage when they see these delivered, and the warden pointedly says he'd hate to be the only one who has something in a wing full of the Have-Nots.
Might as Well Not Be in Prison at All: Clyde still commits murders, even in jail. Turns out getting sent to solitary confinement was part of his plan, since part of the preparations he made before getting arrested included digging a secret tunnel accessible from there.
Mission Control: Clyde pulls a dark version of this trope on Darby, helping him to evade the police and providing an escape vehicle, but only so he'll walk right into his clutches.
Product Placement: Nick's understudy uses a Mac (apparently running Windows), and in one scene the staff prominently rolls in large amounts of Pepsi and Dunkin' Donuts. Every car is a Chevrolet.
Pun-Based Title: The dash is missing from "Law-Abiding" to show that it's the law abiding the citizen, not the other way around.
Red Herring: Nick's understudy is a minor one - around the time Clyde starts amping up his attacks she starts questioning Nick about whether or not he's in the right, and around the time they start questioning whether he has an accomplice inside their system we learn more about her mysterious boyfriend who never shows his face and "isn't ready" to meet Nick - the audience is briefly led to believe that she may be working with Shelton, and the boyfriend stuff was just another trick of his. When she dies, that part of the audience who believed that may even think Shelton pulled a You Have Outlived Your Usefulness on her. By the end of the movie, however, her boyfriend does appear, over the internet to give crucial information.
Roger Ebert also thought this about Colm Meaney's character.
Also Nick has a wife and daughter just like Clyde used to; especially after his daughter gets the DVD in the mail, it's implied Clyde might go after them so Nick will know how it feels to lose them. He never does.
Spanner in the Works: Clyde kills Nick's staff, including his blonde understudy. Said blonde's boyfriend happened to have access to critical information that he wasn't willing to risk his job over...until his girlfriend was killed.
Strawman Political: Although it shows up the dark side of vigilantism, the movie strongly suggests that the justice system is incapable of dealing with violent criminals, and "proves" this with some questionable logic;
"Plea bargains are bad, because here are some arbitrarily bad plea bargains for no adequately explained reason."
"The exclusionary rule is bad, because it got DNA evidence deemed inadmissible when there was no explanation as to what was illegal about how it was obtained."
This Is the Part Where...: Nick says to Cantrell; "Is this the bit where you tell some old fable or wise tale?" Cantrell does.
Clyde asks his cellmate if he's about to threaten him unless he gets some of the steak and eggs meal that's just been delivered to his cell. The inmate gives a Cut His Heart Out with a Spoon threat, so Clyde calmly tells the man he's welcome to join him.
Time Skip: after the sentencing of Darby, cue to 10 years later.
Title Drop: Clyde in court, arguing to be granted bail.
To the Pain: Clyde goes into great detail about everything he's doing and is about to do to Darby.
Trailers Always Spoil: Clyde's past as a government weapon designer and "executive action" mastermind isn't revealed for over half the movie. The reveal itself is in the trailer, along with the Judge's execution, the mass car bombing, the drone attack in the cemetery and Clyde's napalm-induced end.
Villain-by-Proxy Fallacy: Clyde exacts brutal revenge against both of the burglars who were there when his family were killed, even though only one of them carried out the killings, and launches a campaign of terror aimed at bringing down the Justice Department to punish them for the miscarriage of justice that allowed the murderer to get a lesser sentence.
Villain Protagonist: Clyde is briefly alluded to be this in the trailer and the movie when the camera follows him up to the murder of Darby. The movie's actual protagonist turns out to be Nick.
Villains Never Lie: Clyde usually upholds his end of bargains (as long as the other side complies down to the minute), gives hints as to what he's going to do, and confesses when he's ready to. It's conspicuously averted when he tells the judge he's a law-abiding citizen, though (in other words, he tells the truth everywhere except in court). He also falsely tells Darby that he tazed a male cop.
Technically, he did taze a male cop, Darby just assumed that the tazed cop was in the front seat of the cop car, not in it's trunk.
What Could Have Been: Originally Gerard Butler was supposed to be Nick while Jamie Foxx was signed to play Clyde. At the last minute, though, Gerard thought it would be interesting to play Clyde, and asked Jamie if he minded switching roles. Jamie loved Gerard's performance in 300, and thought that as a viewer he would love seeing Gerard "beating people and blowing stuff up". Butler said that having Foxx and himself switch roles would be "awesome".
What the Hell, Hero?: The entire point of the movie. Clyde thinks he's doing this to the entire Justice system, and Nick keeps calling him out on it.
"Fuck [my] Civil Rights." Everyone in the courtroom is looking at Clyde like he's crazy.
Woobie, Destroyer of Worlds: Clyde eventually tries to destroy the entire justice department of Philadelphia, because they failed to properly punish the slayers of his family.
You're Insane!: When Clyde deliberately blows his chance at bail with his Motive Rant, Nick asks him if he's trying for an insanity plea. Other characters speculate that he's gone insane, though if that's the case it doesn't effect Clyde's ability to plan and execute his crimes.