DIVERSITY OF CITIZENSHIP
THE meaning of diversity of citizenship is basically simple. The relevant portion of Article III, Section 2 of the Constitution says: "The judicial power shall extend . . . to controversies between citizens of different states, . . ." In terms of an example, this constitutional provision means that if you are a citizen of New Jersey and I am a citizen of New York, a federal court has jurisdiction in a suit between us. But if we are both citizens of New Jersey, neither of us may gain entry into a national court on this ground.
This rule is clear enough so long as a single individual (plaintiff) faces a single individual (defendant). However, when the two opposing sides in a litigation do not conform to this simple pattern, the Constitution by itself is an insufficient guide to the law. In Strawbridge v. Curtiss,1 decided long before the rule of Swift v. Tyson made the forum in which a case was to be heard so important a factor in determining the substantive law to be applied, there were two plaintiffs arrayed against two defendants. Both plaintiffs and one of the defendants were citizens of Massachusetts, while the second defendant was a citizen of Vermont. In dismissing the suit for want of jurisdiction, Chief Justice Marshall said that he understood the constitutional provision and the act of Congress passed pursuant thereto to mean that a federal court could not obtain jurisdiction on the ground of diversity of citizenship unless each of the plaintiffs in a litigation could show that his citizenship was different than that of each defendant. Marshall's one page opinion gives no reason for this limitation of the diversity jurisdiction beyond the Court's faith in its correctness, nor does it appear that any could have been given. The framers of the Constitution and the authors of the Judiciary Act of 1789____________________