“Out of the clear blue sky…” is a phrase often uttered when recounting the events of September 11, 2001. A description of the temperate fall day, but also a metaphor for how unexpected it all was: the boldness of an attack on U.S. soil coupled with use of commercial airliners—loaded with fuel and innocent people—as weapons of mass destruction. We didn’t see it coming. We weren’t prepared. It changed everything.

What if it happened again, 30 years later, with 30 years of technological advances to exploit?

The Fifth Great Power Competition Conference picks up where the fourth left off. We’ve examined the events leading up to and the day of 9/11 and our immediate response; now, we look forward, asking a roster of former and current military and federal leaders to reflect on whether our nation has made sufficient changes to our security, intelligence, and law enforcement policies and practices to prevent another tragedy from the clear blue sky and what work remains to be done.