• Canadian historian and Oxford professor Margaret MacMillan's new book comes out in October. (Photo: Terrence McEachern/The Guardian)

Few have spent more time considering war than Margaret MacMillan. The Canadian historian and University of Oxford professor — known best for her work Paris 1919: Six Months That Changed the World — is a leading expert on war and international affairs and a frequent voice in the media. Out in October 2020, her new book, The Mark of Cain (an expansion on the lecture series she delivered as the BBC’s 2018 Reith lecturer), unwinds how war and society have always been intertwined. Here, a taste of what readers can look forward to, her thoughts on Canada’s place in the world and more.

On The Mark of Cain

It’s a big topic — perhaps even bigger than I expected! War is part of human society, human society is part of war, and each shapes the other. So I’ve looked at how wars start and are fought, at what happens to civilians, at women in war, at how we try to prevent or control war and at how we think about war, represent it in the arts. I start with the Stone Age and go all the way to the present. It seems to be very much a feature of humanity that we organize ourselves and fight each other.

On war today

We don’t have big state-on-state wars. We have a lot of low-level and civil wars. That is partly a symptom of failed states: where there is nothing left to impose order, you get peoples organized on the basis of religion or ethnicity and sometimes in the same way as criminal gangs, groups that see opportunities and take them. These wars are very hard to stop, as we’ve seen in Afghanistan, Libya and other parts of Africa, Yemen. And as always, it’s the civilians who are exploited and brutalized. These are not merely proxy wars, but a lot of major powers continue to shamelessly and disgracefully funnel weapons into these conflicts to support their own interests.

On a pivotal event historians might write about in 75 years

Historians are always a bit uneasy about thinking of their own times! But if I had to choose, I would look at the first G7 meetings that involved President Trump. That’s when he made it clear that he didn’t care about alliances, about the organizations and friendships that had sustained the United States since 1945. That was a moment in which many people realized something significant had changed.

On Canada role on the global stage

We must continue doing what we’ve always done — we’ve always been quite pragmatic. We are a small power that has spent much of its short history juggling between two big powers, Britain and the United States. We’ve always understood that we have to get on with world powers and preferred to be part of multilateral organizations like the League of Nations or United Nations; there is security in being part of something larger than ourselves. We’re a relatively small group of people occupying a huge part of the Earth, and that has shaped our reactions to the rest of the world and to ourselves.