"This case is about the denial of one of the most fundamental federal rights in the American justice system, the bedrock right—in every case from the lowest village tribunal to the highest court in the land—to hear and respond to all evidence your adversary presents to the court. In an adversarial judicial system like ours, the rule against ex parte communications is the essential guarantor of fair play: it ensures that both sides to a dispute get to see the evidence presented to the court and there is no secret evidence; that such evidence is tested under fire via competing evidence, argument, and/or cross-examination; and that courts are protected from unreliable and inaccurate information by a system that mandates that opposing parties have a right to challenge whatever is presented."