Amid the rubble of the US-Israel war on Iran, a new Middle East appears to be taking shape as a constellation of regional powers jockey for a seat at the table.

Led by Turkey and Saudi Arabia, the grouping stretches from the Gulf across the Caucasus to Central and South Asia, binding together countries with overlapping interests, interlocking partnerships and a shared conviction: that the post-war order should not be dictated exclusively by the US-Israel alliance or Iran and its battered but...