Failure to raise a suppression argument (not just a motion) before the district court equals waiver.

In United States v. Rose, 538 F.3d 175 (3d Cir. 2008), the Third Circuit held that failure to raise specific suppression arguments before the district court amounts to waiver and not just forfeiture. The defendant, who proceeded pro se at trial, filed a motion to suppress certain evidence, putting forth four arguments in support of his claim. The district court denied the motion.

On appeal, now represented by counsel, the defendant appealed the district court's denial of the motion to suppress, but this time asserted a basis for the motion not raised before the district court. Recognizing that the issue called into question the interplay between Fed.R.Crim.P. 12 (which would consider the argument waived) and 52(b) (which would have called for a plain error analysis), and recognizing that its own precedent at times supported one conclusion or the other, the Court definitively stated that Rule 12 controlled the matter, and required a finding of waiver unless the defendant could show "good cause" for not raising the argument before the district court. Because the Court did not find good cause to exist, it considered the defendant's argument on appeal regarding his motion to suppress waived.
and not just a suppression motion itself, constitutes