When a defendant files a motion to suppress, then raises a new argument to support suppression in the court of appeals, is the new argument waived absent a showing of good cause under Federal Rule of Criminal Procedure 12(c)(8), as five Circuits have held, or is the new argument reviewed, at a minimum, for plain error under Federal Rule of Criminal Procedure 52(b), as four Circuits have held?

QUESTION PRESENTED When a defendant files a motion to suppress, then raises a new argument to support suppression in the court of appeals, is the new argument waived absent a showing of good cause under Federal Rule of Criminal Procedure 12(c)(8), as five Circuits have held, or is the new argument reviewed, at a minimum, for plain error under Federal Rule of Criminal Procedure 52(b), as four Circuits have held? i