A prosecutor's inability to prove guilt beyond a reasonable doubt is the most frequently used defense in criminal cases.
What is the most common defense argument?
The most common defense argument is that the prosecution has failed to prove the defendant guilty. Because of the constitutional principles that a defendant is presumed innocent and that the prosecution has to prove guilt beyond a reasonable doubt, this is often the strongest argument the defendant can make.
Will they think I'm guilty if I don't testify?
Defendants have a constitutional right not to testify, and judges and jurors are legally prohibited from taking a defendant's silence as an indication of guilt. However, a risk exists that some jurors may disregard this rule, if only subconsciously.
Motion to Dismiss:
A useful strategy is to make a motion to dismiss at the close of a shaky prosecution case. If the judge grants the motion, the case is over without the defendant having to choose whether to present evidence and create the risk of inadvertently strengthening the prosecutor's case.
What are some of the ways the defense can poke holes in the testimony of prosecution witnesses?
Cross-examining prosecution witnesses and bringing out weaknesses in their testimony requires skill and preparation. The aim is to undermine the credibility (believability) of the witness. The more the defense undercuts the government witnesses, the more likely it is that the judge or jury will form a reasonable doubt as to the defendant's guilt and be willing to acquit her. The issues that the defense typically uses when attempting to cast doubt on prosecution witness testimony are these:
a. Bias - A prosecution witness is biased against the defendant, and therefore is lying or grossly exaggerating.
b. No opportunity to accurately observe - A prosecution witness's observations are mistaken because (1) the lighting was bad; (2) the witness was under the influence of drugs or alcohol; (3) the witness was too far away; etc.
c. Faulty police methods - Evidence from police laboratories is unreliable because machines were not properly maintained, technicians were not properly trained, evidence was not carefully collected or stored, etc.
d. A prosecution witness cuts a deal - A prosecution witness lies to curry favor with the prosecution to get a good deal on criminal charges the witness is facing.
e. Implausible story - A prosecution witness's story is not believable
Can I use the not guilty defense argument if I take the stand to testify or call witnesses?
Yes. Even when defendants testify or call witnesses, they typically still rely on the argument that the prosecution has failed to prove guilt beyond a reasonable doubt. It's important for defendants to realize that even when they present evidence, they usually are not legally obligated to convince the judge or jury that the defense story is accurate. The burden of proving guilt rests at all times on the prosecutor. As defense attorneys frequently remind judges and jurors, "It's not up to us to convince you that the defendant is innocent. The defendant is presumed innocent, and the burden remains on the prosecution to convince you beyond a reasonable doubt of guilt."
Keep the Jury's Attention Focused on the Prosecution's Weak Case
Sometimes, defense attorneys decide not to call witnesses for fear that jurors will erroneously think that by doing so the defense assumes the burden of proving the defense case accurate. The benefits of not presenting a defense case - hopefully impressing on jurors the fact that the entire burden of proof is on the prosecution - may outweigh the risk that jurors will think that the failure to call defense witnesses is evidence of guilt.
Can a defendant try to create a reasonable doubt by introducing evidence that someone else committed the charged crime?
Yes. A defendant can offer evidence that someone else committed a charged crime. However, in order to prevent defendants from "blowing smoke" by throwing blame at numerous possible suspects, evidence of "third-party guilt" is admissible only if the trial judge believes that the defendant's evidence is sufficient to raise a reasonable doubt about the defendant's guilt. Before they can offer evidence of third-party guilt, defendants generally have to produce evidence linking the third party to the crime. Rumors that the third party committed the charged crime, or even evidence that a third party had a motive to commit the crime, is not enough to create reasonable doubt about the defendant's guilt.
Criminal defendants have a constitutional right to present a defense. Therefore, a judge cannot forbid a defendant from offering evidence of third-party guilt simply because the judge believes that the prosecutor has presented an exceptionally strong case.