The civil war divided America’s Christians along axes of geography and theology. These days, Donald Trump and Benjamin Netanyahu, soon to be prime minister again, have wrought a similar sorting. In the words of Eric Alterman, “Israel is a red state. US Jewry is blue.” Alterman is a distinguished professor of English and journalism at the City University of New York. We Are Not One represents four decades of effort, patience and research. Sixty pages of endnotes undergird his arguments, some dating to his student days. Alterman posits that closeness between the US and Israel has oscillated over time and...