Final answer:
Expanding the Supreme Court's original jurisdiction to include cases between individuals would necessitate a constitutional amendment or congressional legislation, due to the limited scope set by the Constitution and the Eleventh Amendment.
Step-by-step explanation:
The Supreme Court's original jurisdiction is outlined in Article III, Section 2 of the U.S. Constitution, which specifies that the Court has original jurisdiction in cases involving ambassadors, public ministers, consuls, and when a state is a party. Expanding this jurisdiction to include cases between individuals would require a constitutional amendment or legislation by Congress, as the current scope is limited and primarily includes cases of significant federal interest or those involving state governments. The Eleventh Amendment further limited the Court's original jurisdiction by restricting cases against state governments brought by citizens of another state or country.