The Department of Homeland Security (DHS) was born out of the tragic events of 9/11. We must remain vigilant in detecting and preventing terrorist threats that may seek to penetrate the homeland from the land, sea, or air. We must continue to build relationships with State and local law enforcement, and the first responders in our communities, to address the threats we face from those who self-radicalize to violence, the so-called "lone wolf" who may be living quietly in our midst, inspired by radical, violent ideology to do harm to Americans-illustrated last year by the Boston Marathon bombing. Addressing each of these types of threats is a matter for the Department of Homeland Security in close collaboration with other departments and agencies. The cornerstone of the homeland security mission has been, and should continue to be, counterterrorism; that is, protecting the Nation against terrorist attacks.