I thought Allapattah said that non-diverse parties across the V contaminates the original basis for providing a federal forum.
that case said that under 1367(b) you can join plaintiffs under Rule 20 who don't meet the amount in controversy for diversity jurisdiction if one of the plaintiffs does...
I'm almost positive that Exxon
also held -- or at least indicated strongly -- that a rule 20 plaintiff who destroys diversity of citizenship is not permitted to join, as this would effectively eviscerate Strawbridge
For instance, we have consistently interpreted §1332 as requiring complete diversity: In a case with multiple plaintiffs and multiple defendants, the presence in the action of a single plaintiff from the same State as a single defendant deprives the district court of original diversity jurisdiction over the entire action. Strawbridge v. Curtiss, 3 Cranch 267 (1806); Owen Equipment & Erection Co. v. Kroger, 437 U. S. 365, 375 (1978). The complete diversity requirement is not mandated by the Constitution, State Farm Fire & Casualty Co. v. Tashire, 386 U. S. 523, 530-531 (1967), or by the plain text of §1332(a). The Court, nonetheless, has adhered to the complete diversity rule in light of the purpose of the diversity requirement, which is to provide a federal forum for important disputes where state courts might favor, or be perceived as favoring, home-state litigants. The presence of parties from the same State on both sides of a case dispels this concern, eliminating a principal reason for conferring §1332 jurisdiction over any of the claims in the action.
In order for a federal court to invoke supplemental jurisdiction under Gibbs, it must first have original jurisdiction over at least one claim in the action. Incomplete diversity destroys original jurisdiction with respect to all claims, so there is nothing to which supplemental jurisdiction can adhere.
So, for example A (NJ) sues B (NY) for $100,000, and A wants to join C(NY) as a rule 20 plaintiff. It will not be allowed, no matter what his amount in controversy is.
However, if C is from MA, it will be allowed.
Side question: What exactly is the procedure for rule 20? Can only the current plaintiff in the lawsuit invoke it? Otherwise, it would be rule 24, correct?