In recent years, a curious thing has happened among many left-leaning clergy and scholars in mainline Christians churches: They’ve embraced the Palestinian cause, vilified Israel, and held Jewish groups at arms length. Is it a case of old-fashioned anti-Semitism? Or is it something worse? Christian religious leaders and scholars from mainline churches are giving the Judeo-Christian heritage a new twist: Islam. Those with a left-wing bent have been working overtime in recent years to find common ground with Muslims – all, ironically, while holding Jewish groups at arms length. Across the country, they regularly participate in “interfaith dialogues” – a...