Robbery defendants have several different options for mounting a defense at trial. Defendants can attempt to convince the jury that the prosecution's evidence doesn't prove that they committed the crime. Defendants can also admit to performing the actions the prosecution has accused them of, but argue that certain facts remove their culpability for the crime otherwise known as an "affirmative defense".
In a criminal prosecution, the government has the burden of proving that the defendant committed the crime beyond a reasonable doubt. This burden of proof means that a defendant can often avoid a conviction by attacking the prosecution's evidence or by offering up evidence that undermines the prosecution's case.
For example, a robbery defendant could offer alibi evidence that they had left the state two days before the robbery took place, or that they had attended an event at the time of the robbery and could provide several witnesses to corroborate that fact. The defense could also challenge eyewitness identifications, security camera videos or other prosecution evidence.
The defendant doesn't have to entirely convince a jury of their actual innocence, but as long as they can cast a reasonable doubt on the prosecution's arguments, the jury should return an acquittal.
A defendant can also offer up proof of their intoxication as an affirmative defense to a robbery charge.
Intoxication that results from actions outside the defendant's control will usually excuse any criminal behavior committed during the intoxication. In this situation, the defendant will have to prove that the intoxication occurred against their will or without their knowledge.
Some states do not allow a voluntary intoxication defense, but others will allow a defendant to plead to a lesser charge because the crime occurred during intoxication. The main question in a voluntary intoxication defense becomes whether or not the defendant could form the necessary intent to commit robbery. Robbery requires a specific intent to use violence to steal another's property, but intoxication could possibly render a defendant incapable of forming this specific intent. In such cases, a voluntary intoxication defense could result in a defendant's conviction on lesser charges with a lower threshold for the defendant's intent.
If someone pushes the defendant into committing a robbery that they would not have committed otherwise, the defendant could have an entrapment defense. Entrapment defenses are difficult to prove, but if the defendant can show that the person who was robbed somehow instigated the event solely to bring charges against the defendant, then they could argue that the victim entrapped them into committing the crime.
If the defendant intended to commit robbery in the first place, however, they will have no entrapment defense even if police officers or other individuals provide an opportunity to commit a robbery in order to collect evidence against the defendant.
If the defendant can show that someone forced them to commit the robbery by threatening them with immediate death or bodily injury, they may have a complete defense to the robbery charges. Proving duress presents difficulties for defendants, and many courts have rejected duress defenses because the defendant did not have a sufficient fear of harm or because the defendant had ample opportunity to avoid committing the robbery without risking death or serious injury.