state of mind required for conviction as an aider and abettor is the same state of mind as required for the principal of- fense." United States v. Centner, 116 F.3d 473 (Table), 1997 WI. 328766, at *2 (4th Cir.1997); United States v. Leder, 23 F.3d 586, 591 (1st Cir.1994); United Stales v. Valencia,