In answer to the question, "How does a jihadist, flying an ISIS flag on his pickup truck, go undetected in the United States long enough to plow into pedestrians, killing at least 15 and injuring many more?"
By acting like a normal American until en route to the attack, when his declaration of allegiance to the Daesh dropped on social media, and unfurling their flag only as he started the attack.
(Please, use the Arabic acronym, it bothers them because it sounds like a slur in Arabic, and is more accurate. ISIL was better on accuracy, since they weren't just claiming Iraq and Syria, but Iraq and al Sham, which means the Levant, way bigger than Syria, not just Syria).
