This can often result out of severe depression, making clients unresponsive and non-committal to any course of legal action. This requires the lawyer to determine at what point a client is simply exercising their basic human (and legally protected) freedom to defend themselves how they wish, and when they have crossed the line into being unable to defend themselves properly. An error in judgment here can cause a massive miscarriage in the lawyer's duties to the client, and/or a greatly diminished quality of justice in the particular instance. Providing a fully zealous defense might, in some very limited cases, not be in the client's best interests. There is one over-riding ethical concern in the practice of criminal defense that is most prevalent in the minds of the public and of new practitioners, and though the frequency of this worry diminishes over time it remains very real. This is, of course, providing a "not guilty" defense for a guilty client. The Rules of Professional Conduct allow for a lawyer to terminate his or her representation of a client only under certain specified instances spelled out in Rule 1.16, among which are:

(1) the client persists in a course of action involving the lawyer's services that the lawyer reasonably believes is criminal or fraudulent;

(2) the client has used the lawyer's services to perpetrate a crime or fraud;

(3) a client insists upon pursuing an objective that the lawyer considers repugnant or imprudent

It is, of course, well established that the known -- either proved or acknowledged -- guilt of a client is grounds for a lawyer to end representation. But the rule as written is far more complicated in situations where the lawyer does not know, but has a compelling assumption, that their client is guilty.

The "reasonable...

Generally, this belief must stem from some actual evidence beyond that which is provided in the case initially. Often, a lawyer is ethically compelled to present a "not guilty" defense at trial at a clients insistence even in the face of overwhelming evidence, the representation of the client being of paramount importance so long as the other responsibilities of the lawyer are not ignored. To that end, a lawyer in this instance must be careful not to suborn perjury or in any other way present or allow to be presented evidence or testimony that he or she "reasonably believes" to be false. Under the Rules of Professional Conduct, though, it cane be difficult for a lawyer to terminate representation. Evidence of a perpetrated crime or fraud that involved the lawyer's services as defined in the second allowance also fulfills the "reasonable belief" of the first, providing no help without evidence. There is some measure of freedom in the third allowance, but the lawyer must show a great deal of fortitude before a court will agree that a client's attempts to defend him or herself are "repugnant" or "imprudent" enough to warrant termination.
The Rules of Professional Conduct do not spell out the necessary actions for all instances of practicing law. Rather, they serve as a way to navigate the many ethical issues that can arise form practice, particularly in the profession of a criminal defense attorney. A careful study and application of these rules, along with a commitment to one's own ethical guideposts, ensures the maintenance of a fair and quality-driven justice system, and the zealous representation of every client.

Reference

Masschusetts Rules of Professional Conduct. Accessed 19 July 2009. http://www.mass.gov/obcbbo/rpcnet.htm