Whether the court of appeals should review an untimely suppression argument for plain error under Rule 52 or require a showing of good cause

QUESTION PRESENTED Before 2014, Federal Rule of Criminal Procedure 12(e) said that “[a] party waives any Rule 12(b)(8) defense, objection, or request not raised by the deadline,” but “[flor good cause, the court may grant relief from the waiver.” A 2014 amendment deleted that provision and replaced it with Rule 12(c)(3), which now says, “If a party does not meet the deadline for making a Rule 12(b)(3) motion, the motion is untimely. But a court may consider the defense, objection, or request if the party shows good cause.” The question presented is: Whether, under current Rule 12, after a defendant has made a timely motion to suppress evidence that did not include a particular argument, should the court of appeals review that argument for plain error under Rule 52, without requiring any special good-cause showing—the rule in four circuits—or must the defendant first prove good cause to the court of appeals—as in the Tenth Circuit and four other circuits?