Objection: Unethical?

Ran across this while perusing criminal law volumes at work yesterday:

§ 114. Ethical Considerations

Invariably, the criminal defense lawyer is asked how the lawyer can in good conscience represent a person known to be guilty. While there is no ethical requirement that the attorney respond, it is nevertheless a good opportunity to explain and defend the criminal justice system in general, without going into the specifics of the case.

Defense counsel is neither judge nor jury. Counsel is an advocate for the client. He or she must exhibit courage and devotion to the client’s cause, and must represent the client zealously within the bounds of the law […]

A lawyer should represent a client competently, and not handle a legal matter which he or she knows or should know that the lawyer is not competent to handle […]

In representation of a client, a lawyer may not knowingly use perjured testimony or false evidence. When the client insists on using perjured testimony or false evidence, the attorney must ask to withdraw from representation. In situations where the attorney learns of perjured testimony after it has been presented, counsel must ask his client to rectify it, and if the client refuses to do so, the lawyer must inform the court.