Donald Trump’s travel ban on refugees and visitors from seven Muslim countries entering the US makes a terrorist attack on Americans at home or abroad more rather than less likely. It does so because one of the main purposes of al-Qaeda and Isis in carrying out atrocities is to provoke an overreaction directed against Muslim communities and states. Such communal punishments vastly increase sympathy for Salafi-jihadi movements among the 1.6 billion Muslims who make up a quarter of the world’s population.
The Trump administration justifies its action by claiming that it is only following lessons learned from 9/11 and the destruction of the Twin Towers. But it has learned exactly the wrong lesson: the great success of Mohammed Atta and his eighteen hijackers was not on the day that they and 3,000 others died, but when President George W Bush responded by leading the US into wars in Afghanistan and Iraq that are still going on.
Al-Qaeda and its clones had been a small organisation with perhaps as few as a thousand militants in south east Afghanistan and north west Pakistan. But thanks to Bush’s calamitous decisions after 9/11, it now has tens of thousands of fighters, billions of dollars in funds and cells in dozens of countries. Few wars have failed so demonstrably or so badly as “the war on terror”. Isis and al-Qaeda activists are often supposed to be inspired simply by a demonic variant of Islam – and this is certainly how Trump has described their motivation – but in practice it was the excesses of the counter-terrorism apparatus such as torture and rendition, Guantanamo and Abu Ghraib which acted as the recruiting sergeant for the Salafi-jihadi movements.