On the 10th anniversary of 9/11, the National September 11 memorial & Museum opened; since then it has welcomed over 21 million visitors from every State in the country and 175 countries around the world. Fourteen years after 9/11, we are still engaged in that struggle. The viral speed of violent extremism has allowed our enemies to spread globally and has brought the war back to our doorsteps. Gone are the days of bin Laden, when extremists relied on couriers and caves to hatch their plots. Today's terrorists are openly recruiting on-line, across borders and at broadband speed. Radical...