How many witnesses is a lawyer allowed to present before the US Supreme Court?

Answer 1

None. The US Supreme Court hears most cases under appellate jurisdiction, and does not listen to witness testimony. In fact, appellate courts may not retry cases, but must accept the factual determination of the lower court and/or trial jury.

The US Supreme Court's role in the appellate process is to determine whether the petitioner/plaintiff's constitutional rights were violated by a law or the legal process, not to determine a defendant's guilt or innocence.

For more information, see Related Questions, below.

Answer 2

The Plaintiff and the Respondent are each allotted 30 minutes to present their arguments; however, either side may choose to allocate part of that time to someone who has filed an amicus curiea ("friend of the court") brief, if lead counsel feels the argument bolsters his or her case.

On occasion, the Solicitor General may petition the Court for permission to present an argument if the United States has an interest in the outcome of the case, but is not a party to it. The Court generally grants these petitions, and allocates extra time for the Solicitor General, and sometimes extends time for amicii or the parties, at the Court's discretion.

Presenting an oral argument before the Supreme Court is quite different from making an argument in a lower court or giving a speech, in that the Justices have the prerogative to interrupt the speaker with questions, challenges and clarifications, and they exercise this right frequently. The clock does not stop when a Justice is speaking, nor when the attorney is responding.