Whether a court may accept a mere allegation of estimated drug quantities from a non-testifying coconspirator informant as satisfaction of the Government's burden of proof requirement to show a specific quantity of drugs sufficient to support the base offense level by reliable 'evidence' without violating due process

QUESTION PRESENTED 1. Ina federal drug conspiracy case where there is no drug seizure, may a court accept a mere allegation of estimated drug quantities from a non-testifying coconspirator informant as satisfaction of the Government's burden of proof requirement to show a specific quantity of drugs sufficient to support the base offense level by reliable "evidence," using the preponderance of evidence standard, after specific objection by the defendant of such drug quantity determination, without violating due process of law?