Final answer:
An opposing party should seek to introduce additional evidence under the rule of completeness when the evidence already presented is misleading or incomplete. This ensures all relevant information is considered to present a fair and complete context, in line with the Sixth Amendment that ensures the rights of the accused to be informed and to challenge evidence against them.
Step-by-step explanation:
An opposing party must seek to introduce additional evidence that they claim should be considered under the rule of completeness when they believe that a piece of evidence that has been presented is misleading or out of context by itself. This rule is designed to ensure fairness by allowing the admission of any evidence that should in fairness be considered along with the part already introduced. For instance, if a prosecutor presents part of the defendant's statement that suggests guilt, the defense might invoke the rule of completeness to compel the inclusion of more of that statement that might provide exculpatory context.
This is a key component of the adversarial judicial system, where both parties must openly share relevant evidence during the disclosure process. The Sixth Amendment guarantees the accused the right to present and challenge evidence, enforcing that they be informed of the charges and evidence against them well before trial, allowing them time to gather complete and supportive evidence for their defense.
Under these principles, when an opposing party believes essential information is omitted that could alter the understanding of the evidence, they should promptly request the inclusion of this supplementary evidence. For instance, in the summary judgment process, where one party may seek a decision without a full trial, presenting complete evidence is vital to determine if the opposing party could not possibly win at trial.