It should NOT.
Defendants who have done the act that forms the basis of their criminal charge often wonder whether they should tell their lawyers. Even if they remain silent, they are concerned that their lawyers will believe that they are guilty, and either won’t want to represent them, or will do a poor job.
First, understand that what’s at stake in your case is whether the prosecution can prove, beyond a reasonable doubt, that you committed the crime with which you’re charged. That’s a different question than asking whether you did the act that’s involved.
The key is the difference between factual guilt (what the defendant actually did) and legal guilt (what a prosecutor can prove). A lawyer asks not, “Did my client do it?” but rather, “Can the Prosecution prove that my client did it?” No matter what the defendant has done, he is not legally guilty until a prosecutor offers enough evidence to persuade the Court to convict.
However, the lawyer may not lie to the judge by specifically stating that the defendant did not do something the lawyer knows the defendant did do. (On the other hand, the lawyer cannot admit guilt against the client’s wishes.) Rather, the lawyer’s trial tactics and arguments must focus on the Prosecition’s failure to prove all the elements of the crime.
Lawyers are ethically bound to zealously represent all clients, those whom they think will be justly found guilty as well as those whom they think are factually innocent. A vigorous defense is necessary to protect the innocent and to ensure that Courts and citizens—and not the police—have the ultimate power to decide who is guilty of a crime.