Wednesday, September 11, 2024, marks the 23rd anniversary of the deadliest terrorist attack in history – 9/11. In the wake of the four coordinated attacks carried out by the Islamist extremist group, al-Qaeda, America went after the attackers and moved to reshape its strategy for national security. More than two decades after 9/11, do Americans feel terrorism is still the greatest threat? And what is the state of national security in the United States today? Three experts tell us how national security is much more than border walls, cyber safety … or taking off our shoes at the airport.