Civil Procedure I
- The district courts shall have original jurisdiction of all civil actions where the matter in controversy exceeds the sum or value of $75,000, exclusive of interest and costs, and is between—
- citizens of different States;
- citizens of a State and citizens or subjects of a foreign state, except that the district courts shall not have original jurisdiction under this subsection of an action between citizens of a State and citizens or subjects of a foreign state who are lawfully admitted for permanent residence in the United States and are domiciled in the same State;
- citizens of different States and in which citizens or subjects of a foreign state are additional parties; and
- a foreign state, defined in section 1603(a) of this title, as plaintiff and citizens of a State or of different States.
If foreigners are on both sides, an American is needed on both sides.
An exception is class actions. If the class action is for over $5 million only a minimal diversity is needed. 28 U.S.C. § 1332(d)(2). This means that only any plaintiff has to be from a different state than any defendant. An exception to this exception is if between one-third and two-thirds of the plaintiffs and the primary defendant are both from the forum state, in which case the court may still deny such a class action. 18 U.S.C. § 1332(d)(2)(3)