Maximum vigilance is needed, and Britain raised its threat level from severe to critical. Public spaces must be made as safe as possible, even as people recognize that more attacks will very likely occur, despite our best defenses. In Britain, as in the rest of Europe and in the United States, it is critical that immigrants, especially Muslims, are not stigmatized. As Richard Barrett, former director of global counterterrorism operations at MI6, Britain’s foreign intelligence agency, said, “engaging the community and letting the community inform us” is one way “to understand why people do this” and to prevent future attacks.
Understanding is critical. The quickest way for open societies to lose the freedoms they enjoy and the Islamic State seeks to destroy would be to whip up divisive ethnic, racist and religious hatreds.