ISIS fighters are battle-hardended and highly motivated, the Iraqi security forces are the complete opposite.
An excellent piece on the disaster unfolding in Iraq via Foreign Policy:
Images emerging from Mosul, Iraq’s embattled northern city, present a familiar scene to fans of zombie movies. Burned-out military vehicles are clustered together on empty streets. At every intersection there is evidence of desperate last stands. Strewn uniforms lay abandoned outside gutted police stations. Hundreds of thousands of civilians have fled for their lives. Mosul is a ghost town where only looters and stray dogs hazard the streets.
But this isn’t a zombie movie. It is Iraq’s second-largest city, the thriving political and economic capital of the country’s Sunni Arab community. In a matter of days between June 6 and 9, the city of 1.8 million people was overrun by the Islamic State of Iraq and al-Sham (ISIS), the al Qaeda affiliate that broke away in April 2013 to fight its own war and which has come perilously close to achieving its dream of a caliphate that reaches from the Mediterranean coast of Lebanon to Iran’s Zagros Mountains. The scenes from Mosul are now being replayed in a dozen other northern cities that have fallen to ISIS and other insurgent elements. […]
Formerly known as al Qaeda in Iraq, ISIS is an Iraqi-led militant group that draws its suicide operators primarily from international volunteers, its foot soldiers from Iraq and Syria, and its money chiefly from a mix of local organized crime rackets. ISIS has used the Syrian conflict to build its strength and assert its independence from al Qaeda’s senior leadership in Pakistan, which disavowed it in February 2014. But the movement’s real ambitions rest in Iraq. The majority of ISIS’s leadership and rank and file are Iraqi, including its emir, Abu Bakr al-Baghdadi. Control of western Mosul would place ISIS in charge of the political and economic capital of Sunni Iraq, a prize of tremendous propaganda value.
ISIS used battle-hardened fighters from the Syrian and Iraqi theaters to smash their way — in a matter of hours — into Mosul’s western neighborhoods from the Jazira, the Syrian-Iraqi desert between the Tigris and Euphrates rivers. The Iraqi government’s weak grasp on the Jazira gave the movement the capacity to surge hundreds of fighters from Iraq and Syria into the battle of Mosul. Even so, the ISIS attack force does not appear to have been large, numbering between 400 and 800 fighters by various estimates. Surprise and aggression allowed the movement to crumble the morale of Iraq’s paramilitary police and army forces in Mosul in three days of hard fighting.
ISIS took on and defeated a government force 15 times their size.
Let that sink in.
The 20 government security battalions in Mosul city seemed to dissolve completely on June 8-9, with significant video evidence of wholesale abandonment of positions by troops who ditched their vehicles and posts, took off their uniforms, and deserted. One photo shows a discarded police brigadier-general’s uniform. The two main security headquarters in Mosul were both overrun and looted by ISIS, as were the provincial governor’s offices. The Mosul branch of Iraq’s Central Bank has reportedly been looted and the historic Assyrian church set aflame. The Iraqi army logistics depot was abandoned to ISIS, who are reported to have burned over 200 U.S.-provided Hummers, trucks, and engineering vehicles. Mosul’s international airport and military airfield also fell to ISIS, with Iraqi helicopters reported destroyed on the ground and armored vehicles being quickly taken to Syria as war booty.