ARTICLE III § 2 clause 2:
In all Cases affecting Ambassadors, other public Ministers and Consuls, and those in which a State shall be Party, the supreme Court shall have original jurisdiction. In all the other Cases before mentioned, the supreme Court shall have appellate jurisdiction, both as to Law and Fact, with such Exceptions, and under such Regulations as the Congress shall make.
This clause indicates whether each of the "cases" and "controversies" mentioned in Article III § 2 clause 1 are to acquire the attention of the "supreme Court" through original jurisdiction or through appellate jurisdiction. In cases in which ambassadors, consuls, etc., are involved, or in which one of the States is a party, the case goes directly to the supreme Court. All other cases must appear first in a lower court, and get the attention of the supreme Court only through the appeals process. —— We find nothing objectionable about this arrangement, so we'll say nothing more about it at this time.