Abstract: For all their ostensible difference and separateness, Judaism and Christianity have a long history of mutual engagement and profound entanglement. I take Daniel Boyarin’s assertion that ‘…the borders between Christianity and Judaism are as constructed and imposed, as artificial and political as any of the borders of the earth’ (2004, 1) as my starting point. But what Boyarin sees as an ongoing process of differentiation between Judaism and Christianity and distinct identity-building in late antiquity, I look for still today in Christian Zionism. The busy border crossing continues to separate people and ideas at the same time as it serves as the meeting place between them, the uncomfortable place where Judaism and Christianity rub up against each other. This paper examines some constructions of the Jewish–Christian border by way of two case studies of prominent religious leaders, each firmly at home in their respective communities, Jewish and Christian, who ventured out to the borderland of Christian Zionism. This is the story of what happened when they returned home to find themselves examined by those who monitor the Jewish–Christian border, and deemed to be over the limit with intoxicants brought over from the ‘other side’.