...plaintiffs have alleged, albeit in insufficiently specific terms, that the defendant corporations (a) knowingly and substantially assisted a principal tortfeasor to commit acts that violate clearly established international law norms, and (b) facilitated the commission of international law violations by providing the principal tortfeasors with the tools, instrumentalities, or services to commit those violations with actual or constructive knowledge that those tools, instrumentalities, or services would be (or only could be) used in connection with that purpose. Such allegations, if proven, clearly satisfy the standard for asserting ATCA liability under an aiding and abetting theory.