Legal Definitions - Department of Homeland Security

The Department of Homeland Security (DHS) is a cabinet-level executive department of the U.S. federal government. Its overarching mission is to protect the United States from a broad spectrum of threats, both foreign and domestic. This includes securing the nation's borders, territories, and critical infrastructure, as well as coordinating responses to emergencies and ensuring the safety of the American public. Established in 2002 in the wake of the September 11th attacks, DHS integrates various federal agencies to enhance national security, manage cybersecurity risks, facilitate lawful trade and travel, and lead disaster preparedness and response efforts.

Here are some examples illustrating the role of the Department of Homeland Security:

• Imagine a cargo ship arriving at a major U.S. port, carrying thousands of containers filled with goods from overseas. Before the containers can be unloaded and distributed, officers from U.S. Customs and Border Protection (CBP) inspect a selection of the cargo, using advanced scanning technology and K9 units, to ensure no illegal contraband or dangerous materials enter the country.

  Explanation: This scenario demonstrates the DHS's vital role in securing the nation's borders and points of entry. CBP is a component agency of DHS, responsible for preventing the entry of illicit goods and individuals, thereby protecting national security and economic interests.

• Following a severe earthquake that devastates a region in California, causing widespread structural damage and displacing thousands of residents, the Federal Emergency Management Agency (FEMA) quickly mobilizes. FEMA coordinates with state and local authorities to set up temporary shelters, distribute emergency supplies, and provide financial assistance to affected individuals and communities for recovery and rebuilding efforts.

  Explanation: This illustrates the DHS's critical function in emergency preparedness and response. FEMA, as part of DHS, leads the federal government's efforts to support citizens and first responders in preparing for, protecting against, responding to, recovering from, and mitigating all types of hazards, including natural disasters.

• A large utility company responsible for managing a significant portion of the nation's electrical grid detects unusual and persistent cyber activity targeting its operational technology systems. The company immediately reports the suspicious activity to the Cybersecurity and Infrastructure Security Agency (CISA), which then provides expert analysis, threat intelligence, and guidance to help the utility strengthen its defenses and mitigate potential disruptions to power supply.

  Explanation: This example highlights the DHS's responsibility for protecting critical infrastructure and addressing cybersecurity threats. CISA, a component of DHS, works collaboratively with both government and private sector entities to enhance the security and resilience of the nation's essential services and digital networks against cyberattacks and other emerging threats.