明显错误规则 plain error rule
The principle that an appeals court can reverse a judgment and order a new trial because of a serious mistake in the proceedings, even though no objection was made at the time the mistake occurred. The issuance of inconsistent instructions to a jury that would result in a miscarriage of justice, for example, can furnish the basis for a new trial, even though no timely and proper objection to the instructions was made. Although a person is entitled to a fair trial, he or she is not entitled to a flawless one; the individual does not have the right to a new trial merely because a HARMLESS ERROR has been committed. 具体例句如下，可供参考：
Plain error is error that is plainly evident from the record and affects a litigant's substantial right(s). Although an appellate court generally only reviews errors brought to its attention by the litigants, it has the discretion to correct plain errors that were not addressed, or forfeited, when not doing so would affect the integrity and reputation of the courts. However, this power is permissive and not mandatory. Plain errors are often the issue in Criminal procedure. Under the Federal Rules of Criminal Procedure Rule 52, "a plain error that affects substantial rights may be considered even though it was not brought to the court's attention." The purpose of the plain error rule is not only to protect the defendant from serious injustices, but to also protect the reputation of the courts and ensure that their decisions follow a fair procedure.
In Rosales-Mireles v. United States, the U.S. Supreme Court reversed a decision by the Fifth Circuit, holding that a clear sentencing error made by the trial court should be corrected in most situations, even when the defendant did not object to the mistake. In so holding, the Court rejected the Fifth Circuit's interpretation of the plain error rule.
The plain error rule's four-part standard requires a court to find the following: The error was not intentionally relinquished or abandoned. The error was clear and obvious, i.e., “plain error.” There is a reasonable probability that, but for the error, the outcome of the proceeding would have been different. The error seriously affected the fairness, integrity, or public reputation of judicial proceedings.
As a final note, the two dissenting justices did not seem to have a problem with the Fifth Circuit changing the plain error rule's legal standard. However, the lack of credibility of the dissenting opinion was demonstrated by the fact that the dissenters had to resort to graphic descriptions of Rosales-Mireles’ other violent crimes, rather than the crime at issue in the case.