Iraq is facing its most severe crisis in years, with the country on the brink of break-up amid lightning offensives by Sunni Muslim militants. How has it happened so quickly? Iraq’s plagued by violence, so what’s new?   The US-led invasion in 2003 unleashed a bloody insurgency led by Iraq’s Sunni Arabs, who controlled the country under Saddam Hussein. Attacks on officials and civilians triggered large-scale reprisals by members of […]