How can you retaliate when there is no return address? Nuclear attribution is not perfect, but there are only nine states with nuclear weapons; the isotopic identifiers of their nuclear materials are relatively well known; and non-state actors face high entry barriers.
跟踪调查的问题其实非常严重。如果没有邮件回复地址我们该怎样报复？核追踪技术远非完美，但只有九个国家拥有核武器；其核材料的同位素标识都明确地为外界掌握；而非国家参与者的进入壁垒很高。