Does the defense always present evidence? Should it?
The prosecution bears the burden of proof in a criminal case—it must prove the defendant guilty “beyond a reasonable doubt” to obtain a conviction. To make this point, some defense lawyers ask the following of prospective jurors during jury selection: “If you had to decide the case right now, without hearing any evidence, would you vote ‘guilty’ or ‘not guilty’?”
The correct answer, of course, is “not guilty.” That’s because the defense technically doesn’t have to prove anything. Rather, its charge is to prevent the prosecution from proving its case.
In order to make this point, some defense lawyers choose not to give an opening statement. Some go a step further and choose not to present any evidence, meaning that they simply cross-examine prosecution witnesses and give closing argument. They don’t call any of their own witnesses to the stand.
A lawyer might internally reserve the decision of whether to call witnesses until the prosecution has presented its case in chief. If, in the lawyer’s judgment, the prosecution’s case wasn’t convincing, he or she might decide not to risk calling unreliable or shaky defense witnesses.
Although choosing not to present a defense can be a viable strategy, many lawyers would rarely dream of passing up the opportunity to affirmatively present an alternate version of facts.