In 2009, President Obama gave a speech in Cairo billed as his address to the Muslim world. “America and Islam are not exclusive, and need not be in competition,” he said. “Instead, they overlap, and share common principles – principles of justice and progress.”

The President’s speech was well intentioned. However, underpinning it is a problematic assumption – one he shared with both his predecessor, George W. Bush, and his ­successor, Donald Trump: that there is a single religio-political entity called the “Muslim world” that can be addressed – or bargained with or cajoled or reformed – in the first place.