It could have been a scene out of Terry Gilliam's prescient film, Brazil (1985): Blast Damages Times Square Recruiting Station. The question is, was the Improvised Explosive Device - IED - planted by a foreign or domestic interest? Wahhabi Islamist or homegrown corn-fed?
When it comes to contagious violence, labels like the above are meaningless. Human beings are very permeable when it comes to mimesis. Violence creates its own justifying myths, as René Girard has taught us. And, sadly as Gilliam's movie predicted, it is probably just the beginning.