The 21-hour marathon talks in Islamabad between the US and Iran ended with no deal. From the rigid red lines to Israel's Lebanon strikes and the standoff at the Strait of Hormuz, here are five key factors that doomed the talks in Pakistan.

ISLAMABAD: As delegations from the US and Iran sit down for critical negotiations in Islamabad, a wide-ranging but complex issues are expected to dominate the discussion.Hosted by Pakistan, the talks aim to build on a fragile ceasefire...