In the case of Platt, Chief Judge, U.S. District Court v. Minnesota Mining & Manufacturing Co., 1963, the Supreme Court dealt with a dispute over whether or not a district court judge could be compelled to testify in a lawsuit involving his own rulings and decisions. The Minnesota Mining & Manufacturing Company (3M) had been sued by another company for patent infringement and during that trial, they alleged misconduct on part of their opponent's attorney who was also involved in an earlier related case presided over by Judge Platt. As part of their defense strategy, 3M subpoenaed Judge Platt to testify about his observations from that previous trial but he refused arguing judicial immunity - the principle which protects judges from being questioned about their official conduct or decision-making process outside of appeals procedures established by law. The Supreme Court sided with Judge Platt stating that compelling him to testify would disrupt the functioning of judiciary system as it would mean subjecting every judicial act to continuous examination; this is contrary to public policy which respects finality and certainty in legal proceedings. Furthermore, it held that any allegations against attorneys should be addressed through appropriate disciplinary channels rather than dragging judges into private litigation disputes.

In the dissenting opinion for Platt v. Minnesota Mining & Manufacturing Co., it was argued that the majority's decision to uphold a lower court ruling, which dismissed an antitrust suit against 3M on grounds of improper venue, was incorrect. The dissenting justices believed that this interpretation of the law could potentially allow corporations to evade legal responsibility by manipulating their place of business or principal office location. They contended that such a narrow interpretation contradicted both legislative intent and previous Supreme Court rulings regarding venue in antitrust cases. Furthermore, they expressed concern about potential implications for future cases involving large multinational corporations with multiple places of business across different jurisdictions.