Then the Greenwich attack happened, and it seemed to confirm the link nativists suspected between foreigners and violence. Police swooped down on a German anarchist club in Soho and rounded up Italians suspected of building bombs. Hundreds of protestors mobbed Bourdin’s funeral cortège, hissing “No bombs here!” “Go back to your own country!”

With the episode fresh in the public mind, the leader of the Conservative Party, Lord Salisbury, introduced a parliamentary bill to restrict immigration. The British “have always loved to consider this island as the asylum of those who are defeated in political struggles,” Salisbury acknowledged, but the Greenwich incident “caused an entire change in that idea of the right of asylum.” There were terrorists, there were refugees, sometimes there were terrorists who were also refugees, and so refugees should no longer be allowed in.

Salisbury was wrong. There was no evidence that “England is to a great extent the headquarters, the base, from which the Anarchist operations are conducted,” as he had said. There was even less to link anarchists and Jewish refugees. Mobilizing fear of anarchists to promote immigration restrictions made good politics but very bad policy.

If public safety was really the objective, keeping out continental Europeans achieved next to nothing. As Salisbury knew, by far the greatest terrorist threat came from Britain’s own subjects: Irish nationalists. In the 1880s, Irish revolutionaries had dynamited the London Underground, the Tower of London and the House of Commons, causing far more carnage than a foreigner ever did.

Bourdin’s bomb was presumed to be the only anarchist incident in British history, and anarchists (unlike Communists) didn’t succeed in overthrowing governments. In retrospect it looked to Joseph Conrad, who used the incident as the inspiration for his 1907 novel “The Secret Agent,” like “a blood-stained inanity of so fatuous a kind that it was impossible to fathom its origin by any reasonable or even unreasonable process of thought.”

But that is not to say that anarchism had no impact.

Anarchism helped shape modern immigration restrictions across Europe and the United States. It underpinned the consolidation of international policing when criminal justice agents convened in 1914 to address the threat of anarchism, and formed what became today’s Interpol. It carved grooves in Western minds about foreignness and terrorism that we can slip into almost without thinking.