A defense strategy typically emerges as a defense lawyer finds out about the prosecution's evidence and the defendant's version of events. The process of developing a defense strategy is usually fluid, and it varies from one case to another. For example, the attorney's tentative theory of defense will influence the topics the attorney asks about. The defendant's answers to those questions may in turn affect the attorney's defense strategy.
This does not mean that defendants and their attorneys collaborate to make up false stories. For a number of reasons, defendants usually benefit from telling their attorneys the truth as the defendants perceive it. However, multiple versions of truth can coexist in the defense of criminal charges. For instance, assume that a woman is charged with murdering her boyfriend. The "truth" may consist of the woman's acting in self-defense, or it may consist of the boyfriend's physical and verbal abuse of the woman in the months preceding the killing, or it may consist of both. A defense strategy is a product of a defendant and defense attorney fitting together the version of the truth that is most likely to produce a satisfactory defense outcome--a verdict of not guilty, a verdict of guilt of a lesser charge, or an acceptable plea bargain.
As may be apparent, the account of events a defendant might tell spontaneously could omit these and other elements that are both accurate and helpful. This is why defendants and their attorneys have to work together to develop a version of events that will best benefit the defense.
For example, assume that a defendant is charged with burglary. The prosecution's evidence consists of the defendant's confession to the police shortly after the defendant's arrest, and an eyewitness who "is pretty sure that the defendant was among the burglars." The defendant has told his attorney that a couple of the defendant's friends planned and carried out the burglary; he had never been in trouble but stupidly went along with them so as to look good in their eyes; and that the police didn't tell him that he had a right to remain silent or have an attorney present during questioning.
This is in essence a "confession" story. Nevertheless, the defendant and the defense attorney may adopt a defense theory that "overzealous police officers tried to paper-over weak eyewitness identification evidence by improperly extracting a confession from a naive suspect." This theory is consistent with the defendant's version of events, and it describes events in a way that favors the defense.
Pursuing this strategy, the defense attorney might file a pretrial motion seeking to bar the prosecution from offering the confession into evidence because the police failed to comply with Miranda procedures. In addition, the defense attorney might develop arguments that the eyewitness identification evidence is too weak to prove guilt beyond a reasonable doubt. The goal of this strategy may be either to achieve a not guilty verdict at trial, or to weaken the prosecutor's case enough to persuade the prosecutor to agree to the defense's desired plea bargain. Even if the defendant is convicted, the defense attorney may rely on the defendant's lack of a prior criminal record, and the fact that he was a dupe who passively participated in a crime orchestrated by others, to argue for minimum punishment.
In addition, attorneys can coach defendants by fully explaining the charges against them, and by imparting as much as is known of the prosecution's story, before starting to question them about a version of events. Defendants need such information if they are to tell an accurate version that does not leave out information potentially helpful to the defense.
For example, assume that Rhoda is charged with the crime of "receiving stolen goods." Before seeking to elicit Rhoda's version, Rhoda's lawyer ethically may tell her something along these lines:
"Rhoda, you're charged with receiving stolen property. What that means in plain English is that you personally are not charged with stealing anything; the claim is that you obtained property even though you knew for a fact that someone else had stolen it. Now, I'd like to find out from you as much as you can tell me about what happened. But first let me tell you that the police report and a brief talk I had with the D.A. indicate that they claim you are a middleperson in a ring that deals in stolen watches. A couple of guys named Bernie and Chuck supposedly steal watches from warehouses, drop some of the cartons off in your garage, and you later distribute them to jewelry stores around town. They've got the names of some of the stores you supposedly deal with. Unless you have any questions, why don't you tell me what you know about all this?"
Once Rhoda has this information, she will be in a good position to help her attorney by making sure she gives him whatever details she has that will shed a more favorable light on the facts being alleged by the prosecution.
Another reason to tell attorneys the truth is that the truth may reveal the defendant to be guilty, but only of a less-serious offense. For example, a defendant's truthful story may reveal that a defendant charged with assault with a deadly weapon is at most guilty of simple assault, a much less-serious crime. If the defendant lies and insists on complete innocence, the defense attorney may be unable to arrive at a realistic plea bargain. And if the case goes to trial, the defense attorney may not be able to ask the jury to convict on the lesser offense rather than the greater offense, because the defendant did not disclose any facts suggesting such a result.