Can a defendant argue for the first time on appeal that the dual sovereign exception to the double jeopardy clause does not apply because the forfeiture was a federal forfeiture?

Defendant argues for the first time on appeal that the dual sovereign exception to the double jeopardy clause does not apply because the forfeiture was in fact a federal forfeiture. "Issues not presented to the trial court cannot generally be raised for the first time on appeal." United States v. Flores-Payon, 942 F.2d 556, 558 (9th Cir.1991). However, we find it is appropriate to address defendant's argument because he raises a purely legal issue and the government has failed to establish prejudice. See id.