Final answer:
A lawyer must not knowingly make a false statement of material fact or law to a third person, as legal ethical standards require truthfulness and integrity. Cases like Glasser v. United States and Strickland v. Washington underscore the importance of effective counsel and the ethical duties of lawyers, including advising clients of legal consequences such as deportation risks.
Step-by-step explanation:
In the course of representing a client, a lawyer must not knowingly make a false statement of material fact or law to a third person. In legal practice, the obligation for a lawyer to remain truthful when dealing with others is paramount. For instance, as per the principles established in the case of Glasser v. United States, a lawyer's conflict of interest can violate a client's Sixth Amendment rights. Moreover, the Supreme Court has set forth standards in Strickland v. Washington ensuring that ineffective assistance of counsel requires both a showing of substandard performance and prejudice to the defense. Furthermore, in Padilla v. Kentucky, the Court recognized that attorneys have a duty to inform clients of certain legal consequences, such as immigration repercussions of criminal convictions.
When it comes to truthfulness towards third parties, a lawyer must not engage in actions like misrepresentation of facts, which involves distorting the truth. This ethical rule is in line with the prohibition of actions such as plagiarism, cheating, and fraud, which are all contrary to the professional conduct expected of attorneys. A lawyer also cannot impair an obligation of contracts, abridge the privileges or immunities of citizens, or deny due process and equal protection of the laws. Lawyers are bound to uphold not just the letter of the law but also its spirit, maintaining professional integrity and the rights afforded to their clients and all parties involved.