The Trump administration is instructing immigration officers to deny permanent residency to applicants who have expressed anti-Israel views or joined pro-Palestinian protests, according to internal Department of Homeland Security documents obtained by The New York Times. The shift, which marks a dramatic expansion of ideological vetting in the US immigration system, comes just as Gallup polling data reveal that for the first time in a generation more Americans say they sympathise with the Palestinians than with Israelis — 41 per cent to 36 per cent, reversing a double-digit advantage that Israel had held since 2001.

The confluence of a hardening administrative apparatus and softening public opinion sets the stage for a contentious debate about speech, allegiance and the limits of criticism of a foreign government.