The often controversial Niall Ferguson, 49, is one of the world’s most prominent historians. A specialist in international and economic history, a professor at Harvard and a senior research fellow at Oxford, Ferguson is the author of The Ascent of Money and Civilization: The West and the Rest, among other works. Married to feminist and atheist activist Ayaan Hirsi Ali, the British-American scholar is also a vocal critic of U.S. President Barack Obama. Ferguson’s latest book, The Great Degeneration, which originated in 2012 as the BBC’s prestigious Reith Lectures, condemns what he sees as an era of decline in the West, pinning the blame on our deteriorating institutions.

Q: You have a reputation, rightly or wrongly, as a Western triumphalist, and now you’re writing about Western decline. Is this an about-turn?

A: I’m not sure there’s anything triumphalist about the writing I’ve done. In both Empire and Colossus I argued that it was highly unlikely that the United States could replicate British-style empire. Colossus is a pessimistic book— its subtitle was actually The Rise and Fall of the American Empire. That was 2004. Civilization similarly was a book about the end of Western ascendancy. So I think this book is a fairly natural sequel. There are people who like to pretend that I am a neo-conservative triumphalist, which I never was. They just never bothered to read my books because it’s much easier just to make these things up....