Stephen Bannon, President Donald Trump’s chief strategist and the driving force behind the administration’s controversial ban on travelers from seven Muslim-majority countries, has a favorite metaphor he uses to describe the largest refugee crisis in human history.

“It’s been almost a Camp of the Saints-type invasion into Central and then Western and Northern Europe,” he said in October 2015.

“The whole thing in Europe is all about immigration,” he said in January 2016. “It’s a global issue today — this kind of global Camp of the Saints.”

“It’s not a migration,” he said later that January. “It’s really an invasion. I call it the Camp of the Saints.”

“When we first started talking about this a year ago,” he said in April 2016, “we called it the Camp of the Saints. ... I mean, this is Camp of the Saints, isn’t it?”

Bannon has agitated for a host of anti-immigrant measures. In his previous role as executive chairman of the right-wing news site Breitbart — which he called a “platform for the alt-right,” the online movement of white nationalists — he made anti-immigrant and anti-Muslim news a focus.

But the top Trump aide’s repeated references to The Camp of the Saints, an obscure 1973 novel by French author Jean Raspail, reveal even more about how he understands the world. The book is a cult favorite on the far right, yet it’s never found a wider audience. There’s a good reason for that: It’s breathtakingly racist.