two parties are engaged in civil action, each is represented by a lawyer. If the lawyer of one party approaches a witness who discloses information that supports the other parties case AND that lawyer later presents affidavit evidence that is in contradiction to what the witness told him AND although he named the witness he does not call him to court - Has that lawyer breached the duty of care [tort] he owes the court and the opposing party? ie because the lawyer is obliged to comply with professional rules and a duty to the court, the opposing client is effectlively in a relationship with that lawyer via the professional standards designed to protect that other party from malicious acts. There is no direct contract between the party and the opposing parties lawyer but there is a duty of care and one could argue that professional standards establish a minimum standard contract between the person and the opposing parties lawyer. There are obligations and rules that are designed to establish a relationship of trust bewteen these opposing parties - the rules of engagement - every in the litigation is conncted via these rules. So if a lawyer acts in a way that is in breach of professional standards and the obligations they have to uphold justice. The other party has suffered a loss because of these acts.
1 Answer from Attorneys
You start from a completely false premise: that an attorney owes some duty of care to the court and opposing party. A lawyer only owes the court a duty not to knowingly allow perjury or present false evidence, and to show proper respect for the court and court rules. A lawyer owes no duty of any kind whatsoever to the opposing party.
A lawyer has NO duty to the opposing party other than to beat them without breaking the law or violating any of the Rules of Professional Conduct. The is no law or Rule that require a lawyer to present testimony or evidence that is negative for his or her client's case. The only reason we have lawsuits is because there is conflicting evidence. A lawyer is only obligated to present the evidence that supports the client's case. Just because we know there is conflicting testimony doesn't obligate us to present it, or even believe it. That's the other lawyer's job.
A lawyer is not even under a duty in a civil case to disclose negative evidence unless asked for it in discovery (in criminal law the prosecution is required to volunteer exculpatory evidence even if not requested). The only trust between opposing counsel is we can trust our opponent to do whatever is in their client's best interests within the law and rules. We can only trust each other to be open about negative evidence if it advances the client's cause in some way, or we are required to in discovery. We certainly have no duty to the opposing party.