Nivica v. United States

holding that district court has broad discretion in admitting expert testimony and that district court's decision qualifying a witness as an expert will not be reversed unless manifestly in error | holding that district court has broad discretion in admitting expert testimony and that district court’s decision qualifying a witness as an expert will not be reversed unless manifestly in error | defendant who does not testify may not challenge ruling regarding the scope of permissible cross-examination | defendant who does not testify may not challenge ruling regarding the scope of permissible cross-examination | risks of juror questioning of witnesses are "compounded in a criminal case" | risks of juror questioning of witnesses are "compounded in a criminal case"