Nearly eight years after it was agreed, the treaty on suppression of unlawful acts relating to international civil aviation entered into force on 1 July.

Known as the Beijing Convention, it updates earlier protocols, criminalising new and emerging threats against air transport. It was drawn up partly in direct response to the 9/11 attacks on the USA, to strengthen countermeasures and deter those who might choose to employ civil aviation as a weapon of conflict.

The agreement was reached on 10 September 2010, the eve of the ninth anniversary of 9/11, and the US representative, Clifton Johnson, stated that he could think of “no more fitting and hopeful a way” to commemorate the occasion than with the adoption of the new treaty.

While the Beijing Convention was not intended to address the use of civil aviation as a weapon in the sphere of political, rather than armed, conflict, the coercive intimidation of sanctions is nonetheless a form of hostility, and one which is not necessarily without consequences for the well-being of innocent citizens.

President Donald Trump’s decision to abandon the joint Iranian nuclear deal, whether driven by genuine concern or a triumph of ego over rationality, leaves his government open to uncomfortable accusations over passengers’ vulnerability.

The obvious retort – that the fault lies entirely with the Iranian government for failing to bow to sanction pressure – is a paltry attempt to claim the moral high ground. Sanctions have not stopped Iranians flying, just drafted them as uninformed and unwitting arbiters of air safety.

Previous US administrations have recognised the risk of being perceived as a tacitly allowing passengers to be put at risk, and the European negotiators have recently pressed the current US government to cease using civil aviation safety as ammunition in its dispute with Iran.

Clifton Johnson referred to the “common humanity” of 9/11’s casualties, and described the Beijing Convention – which the USA has yet to ratify – as demonstrating the “most promising” of 9/11 legacies, that of international co-operation to counter the scourge of terrorism.

Trump’s withdrawal from the Iranian deal leaves the US commitment to international co-operation in doubt, and its interest in common humanity – particularly those entrusting their lives to air transport – open to question.