The Second Circuit last week rendered another important ATS decision addressing some of the most troublesome issues relating to human rights litigation against corporate defendants. In the case of Abdullahi v. Pfizer, the Second Circuit was faced with the question of whether involuntary medical testing on humans violates international law.

Perhaps the most significant part of the decision was the spirited debate between the majority and the dissent over what constitutes actionable customary international law under Sosa. Scholars have long struggled with the Paquete Habana versus Filartiga approach to finding customary international law. This debate is nicely encapsulated in the majority and dissenting opinions….