(CNN) -- Last week, Iraq's second-largest city of Mosul fell to the Islamic State in Iraq and Syria, or ISIS. In a few hours, the city's security forces had dropped their weapons and uniforms and fled. Since then, the militants introduced a political charter in Mosul and marched south, seizing additional towns en route to the capital, Baghdad. In taking Mosul alone, ISIS gained as much as $425 million in cash, an unspecified quantity of gold bullion, huge amounts of light and heavy weaponry (mostly U.S.-made) and probably hundreds of new recruits from three main detention centers, all which were overrun.
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Charles Lister: ISIS gaining recruits, cash and weapons in inevitable offensive in Iraq
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Lister: ISIS gains from what has become a Sunni uprising, but its ties to Iraq's Sunnis unstable
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He says once ISIS brutality starts, support may change and ISIS will be forced back
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Lister: ISIS a formidable, fanatical force bent on rapid results but may fail in long term
ISIS has substantial roots in @placeholder, where it managed to remain a potent force during and after the U.S. troop "surge."
Considering recent events and its march to @placeholder, this objective might not be so inconceivable.