US-led coalition strikes in Syria aimed at weakening radical Islamists may bring together previously warring hardline groups, who increasingly perceive the west as a shared enemy.

Fighters from Jabhat al-Nusra, al-Qaeda’s affiliate in Syria, and other Islamist groups say they are trying to negotiate a truce with the Islamic State of Iraq and the Levant (Isis), whose lightning advance across a third of both Iraq and Syria was the casus belli for foreign air strikes in the region.

Before the strikes, the two jihadi forces had been at war for nearly a year over divergent strategies and competition for resources. These clashes helped more moderate rebel forces trying to topple President Bashar al-Assad regain some of the influence they had lost, as Islamists came to dominate the opposition in Syria’s three-year conflict. […]