Italy is beginning to understand a lesson the entire freedom-loving West must internalize: governments should not wait for a jihadi terrorist attack before taking lawful action against a credible jihadist threat.

Italian authorities recently deported a 30-year-old Tunisian whom they considered dangerous to public security and suspected of Islamist radicalization. Italy’s counterterrorism framework allows authorities to expel certain non-EU foreign nationals suspected of terrorist connections without waiting for innocent people to be murdered.

But this raises a much harder question for Italy, Britain, France, Germany, the Netherlands, America, Israel and other democracies: What happens when someone supporting terrorism already possesses citizenship?