The Saudis could never reconcile themselves to the US-led invasion of Iraq, not because it toppled Saddam Hussein but because it led to Shia majority rule in an Arab country. When Hosni Mubarak was toppled by Egypt’s popular revolt in 2011, Riyadh accused Mr Obama of betraying a US ally. Saudi perceptions of US complacency in the face of Iran’s advances in Iraq, Syria, Lebanon and Yemen are a grievance far outweighing western perceptions of Isis jihadism as the main threat in and from the Middle East. After the Iraqi city of Mosul fell to a lightning Isis offensive in 2014, even the late Prince Saud al-Faisal, the respected Saudi foreign minister, remonstrated with John Kerry, US secretary of state, that “Daesh [Isis] is our [Sunni] response to your support for the Da’wa” — the Tehran-aligned Shia Islamist ruling party of Iraq.