In practice, the immigrant masses and the handful of anarchists were quite distinct. But since people believed — as tabloids and sensation novels continually reminded them — that some foreigners might be bomb-throwing revolutionaries, they didn’t think rationally about the differences. They saw what Wilkins called “destitute and degraded foreigners” bringing “pauperism, vice and crime.”

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.