When π (Tennessee) sues ∆ (Idaho) and the latter impleads T (Florida) but π subsequently files an upsloping 14a claim against T, what impacts jurisdiction under § 1367(b)?

In this scenario, the key factor relates to the nature of the claims and the parties involved. Under § 1367(b), when a plaintiff brings a claim against a third-party defendant (T, in this case) after the third-party defendant has been impleaded, specifically in a situation where diversity jurisdiction is applied, the court must assess whether the jurisdiction remains intact based on the original basis for jurisdiction.

The critical point is that when the plaintiff (π), who is from Tennessee, seeks to assert a new claim against a third-party defendant (T) who is from Florida, the jurisdiction over this claim is scrutinized because the original case was based on diversity jurisdiction. § 1367(b) limits supplemental jurisdiction for claims that involve parties who are added under Rule 14 (impleader) when exercising supplemental jurisdiction over claims where the original jurisdiction was diversity-based and the parties are from different states.

Given this context, the outcome is that the claim against T could be barred because the claim would not meet the requirements for supplemental jurisdiction since it diverts away from the original diversity context. This creates a barrier to exercising jurisdiction for π's claim against T, thus supporting the determination that jurisdiction is indeed barred under these strict conditions, particularly because diversity is the