A century after the British and French foreign ministers sat down to draw the map of the Middle East, the region they created is unravelling by the hour. The potential for prolonged political-religious wars within and across boundaries, involving both local and foreign forces and militias and governments, is great.
There are several explanations for our arrival at this point. The US decision in 2003 to oust the regime of Saddam Hussein in Iraq, followed by policies that reinforced sectarian rather than national identities, is one. This also helped to bring about a region in which Iran was left with few constraints on its ability to back Shia factions in Iraq, up to then its main regional rival, and elsewhere.
The administration of Barack Obama comes in for its share of responsibility. After inheriting an improved Iraq, thanks to the surge undertaken by the George W Bush administration, it should have pushed harder for a residual US or international force to remain. Such a presence could have damped local rivalries and trained Iraq's army.
The president could also have done more in neighbouring Syria once he determined that the regime of Bashar al-Assad had to go. By neither acting against Mr Assad directly when he used chemical weapons nor providing military aid to those non-extremists opposing him, he helped to create a vacuum increasingly filled by radical jihadists such as Islamic State of Iraq and the Levant, known as Isis.