Is it proper to cross examine for the purpose of discrediting the reliability or credibility of an adverse witness whom you know to be telling the truth?

Introduction to Criminal Justice Siegel/Worrall

Ethical Issues As an officer of the court, along with the judge. prosecutors, and other trial participants, the defense attorney seeks to uncover the basic facts and elements of the criminal act. In this dual capacity as both a defense advocate and an officer of the court, the attorney is often confronted with conflicting obligations to his or her client and profession.

In a famous work,Monroe Freedman identified three of the most difficult problems in\ lying the professional responsibility of the criminal defense lawyer:

Is it proper to cross examine for the purpose of discrediting the reliability or credibility of an adverse witness whom you know to be telling the truth?

Is it proper to put a witness on the stand when you know he will commit perjury?

Is it proper to give your client legal advice when you have reason to believe that the knowledge you give him will tempt him to commit perjury