Trump's abrupt withdrawal from Syria may allow ISIS to come back with a vengeance — using the group's time-tested strategy

US President Donald Trump's announcement that he would remove US troops from northeastern Syria, where as many as 12,000 ISIS fighters are being held by Kurdish-led Syrian Democratic Forces, stoked concerns about an ISIS prison break similar to the one in Iraq that fueled the group's international campaign of terror and brought rise to the caliphate.

In 2012 — before ISIS was even called ISIS, back when it was called al Qaeda in Iraq (AQI) — AQI started an operation called "Breaking the Walls." The year-long operation involved driving vehicle-borne improvised explosive devices (VBIEDS) to spread terror, and staged eight prison breaks.

According to a 2013 report from the Institute for the Study of War, the campaign ended after AQI broke into Abu Ghraib prison, releasing at least 500 prisoners, many of whom were detained for terror-related charges. Two of the prison breaks, the report says, released "hard-core veterans who had likely participated in AQI's signature VBIED network during the period 2006- 2007."

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