In a little-noticed filing before an Oregon federal judge, the US Justice Department and the FBI conceded that stopping US and other citizens from travelling on airplanes is a matter of “predictive assessments about potential threats”, the government asserted in May.

“By its very nature, identifying individuals who ‘may be a threat to civil aviation or national security’ is a predictive judgment intended to prevent future acts of terrorism in an uncertain context,” Justice Department officials Benjamin C Mizer and Anthony J Coppolino told the court on 28 May.

“Judgments concerning such potential threats to aviation and national security call upon the unique prerogatives of the Executive in assessing such threats.”

It is believed to be the government’s most direct acknowledgement to date that people are not allowed to fly because of what the government believes they might do and not what they have already done.