Sunni militants extended their control over parts of northern and western Iraq on Wednesday as Iraqi government forces crumbled in disarray. The militants overran the city of Tikrit, seized facilities in the strategic oil refining town of Baiji, and threatened an important Shiite shrine in Samarra as they moved south toward Baghdad. The remarkably rapid advance of the Sunni militants, who on Tuesday seized the northern city of Mosul as Iraqi forces fled or surrendered, reflects the spillover of the Sunni insurgency in Syria and the inability of Iraq’s Shiite-led government to pacify the country after American forces departed in 2011 following eight years of war and occupation. By late Wednesday, witnesses in Samarra, 70 miles north of Baghdad, were reporting that the militants, many of them aligned with the radical Islamic State of Iraq and Syria or ISIS, were on the outskirts of the city. They […]