That brings us to Promised Land, Crusader State by Walter McDougall. Tell us about the book.

As the title implies, it explores the two sides of American exceptionalism. The term American exceptionalism, I should elaborate, derives from the idea that America is not just any country. It is a special country with a special mission and, in purposefully biblical terms, that mission is to redeem an otherwise sinful world. McDougall divides American foreign policy into “Old Testament” and “New Testament” phases. Others would call the tendencies exemplar and missionary impulses respectively. His “Old Testament” presents a modest America to which foreign nations can look for example. His “New Testament” offers America as a missionary nation going abroad to lecture on the Good Book.

There is a striking continuity here. Even the most hard-nosed devotees of realpolitik (for instance Richard Nixon) are always in the end reduced to selling American foreign policy to Americans in biblical terms – referring to America as a city on the hill, a New Jerusalem. The language of American exceptionalism strikes a chord with Americans. President Obama, for one, came into office promising to be more modest in our dealings abroad. But to listen to him today you might think you’re listening to his predecessor. The lanes for discourse in American foreign policy are extremely narrow and well-hewed. When presidents talk about foreign policy they enjoy far less room to manoeuvre than they might have hoped for. They always veer back onto the path of exceptionalism.

McDougall disagrees with what he calls “American meliorism”, America’s attempt to remake the world in its image. Can you make his argument and then tell me if or why you disagree?

The strength of McDougall’s book is its taxonomies, the distinction he makes between the promised land, on the one hand, and then the crusader state on the other. The weakness of his book is located in its normative sections. McDougall, a Vietnam veteran, clearly prefers an America that, while it may have a conception of itself as a promised land, leads by example. He believes that during the Spanish American War America was transformed into a crusading state, and that after 1898 we were guided by a missionary impulse that led us into disaster in World War I and then into successive catastrophes during the Cold War, one of which he experienced up close and personally. In McDougall’s rueful telling, this tradition reached its apogee in Vietnam. Hence meliorism – the tendency to believe we can ameliorate the human condition, which he views as being fixed and fallen. McDougall nicely details how this messianic impulse has led us astray. But I believe his reading of our downfall is overly programmatic.

Let’s talk about Ordinary Men, Christopher Browning’s dissection of a 500-person German police battalion that shot 38,000 Jews and transported 45,000 to the gas chambers.

Browning famously wrote, and here I’m paraphrasing, “If the men of Police Battalion 101 could become killers, what group of men could not?” The takeaway from reading this horror-filled book is that depredations on the scale of those that Browning describes can be perpetrated anywhere and by anyone. Using first-hand accounts and official records, he describes how 500 ordinary men, Germans unfit for the draft, are given a mission to liquidate all the Jews in a village as well as an opportunity to excuse themselves. The vast majority chose to shoot innocent women and children. Over the next two years, they ended up murdering tens of thousands of people. This relates to my worldview in the sense that humanitarian interventionists are guided by the conviction that “never again” should we allow horrors of the type depicted in this book to repeat themselves. Certainly not if we have the means to prevent it and at acceptable cost.

So the fact that ordinary people can be turned into killing machines with ease, as Browning demonstrated, gives flight to the beliefs of liberal hawks like yourself?

The Holocaust looms large in American foreign policy. Unlike during World War II, when we were otherwise consumed, America now has the power to stop slow-motion slaughters. The Holocaust is always part of the debate when American humanitarian intervention comes up. Some people attribute that to the over-representation of Jews in American foreign policymaking. But I think the Holocaust stands as an example for non-Jewish and Jewish Americans alike, of what should never be allowed to happen on America’s watch.

Onto a book that would definitely appear on the syllabus of any international relations course: John Lewis Gaddis’s Strategies of Containment.