There is no statutory definition of homeland security that reflects the breadth of the enterprise as currently understood. Although there is a federal Department of Homeland Security, it is neither solely dedicated to homeland security missions, nor is it the only part of the federal government with significant responsibilities in this arena. The Department of Homeland Security (DHS) was established by the Homeland Security Act of 2002 ( P.L. 107-296 ), which was signed into law on November 25, 2002. The new department was assembled from components pulled from 22 different government agencies and began official operations on March 1, 2003. Since then, DHS has undergone a series of restructurings and reorganizations intended to improve its effectiveness and efficiency. Although DHS does include many of the homeland security functions of the federal government, several of these functions or parts of these functions remain at their original executive branch agencies and departments, including the Departments of Justice, State, Defense, and Transportation. Not all of the missions of DHS are officially "homeland security" missions. Some components have historical missions that do not directly relate to conventional homeland security definitions, such as the Coast Guard's environmental and boater safety missions, and Congress has in the past debated whether FEMA and its disaster relief and recovery missions belong in the department. Some criminal justice elements could arguably be included in a broad definition of homeland security. Issues such as the role of the military in law enforcement, monitoring and policing transfers of money, human trafficking, explosives and weapons laws, and aspects of foreign policy, trade, and economics have implications for homeland security policy. Rather than trying to resolve the question of what should or should not be considered a part of homeland security, this report is a survey of issues that have come up in the context of homeland security policy debates. After initial discussion of the definitions of homeland security, the homeland security budget, and the role of homeland security actors in the intelligence community, the report groups the issues into five general themes: Counterterrorism and Security Management; Border Security and Trade; Disaster Preparedness, Response, and Recovery; Cybersecurity; and DHS Management Issues As each topic under these themes is introduced, the author of the section is listed, along with their contact information. In many cases, a specific CRS report is highlighted as a source of more detailed information. This report is neither exhaustive nor exclusive in its scope, but representative of the broad array of issues likely to be taken up in one way or another by the 115 th Congress in the coming months. The report includes many issues that were touched upon in the 114 th Congress through legislation or hearings, and remain unresolved. Some specific issues or issue areas are explored from a variety of perspectives in other CRS work (e.g., issues with law enforcement, domestic policy, or national security aspects), and the reader is encouraged to reach out to CRS directly or explore the CRS website to take full advantage of the products available to them on these matters. While this report may be updated, it should be viewed as an introduction, not a legislative tracker. Therefore, some issues currently under debate are not included as a focal item in this report, as the state of the debate is highly dynamic (e.g., the Administration's proposed construction of a wall on the U.S.-Mexico border), and other CRS analytical products provide more current analysis than can practically be provided in a report of this breadth. [author name scrubbed], Specialist in Homeland Security Policy and Appropriations ( [email address scrubbed] , [phone number scrubbed]) For more information, see CRS Report R44621, Department of Homeland Security Appropriations: FY2017 , coordinated by [author name scrubbed], and CRS Report R44052, DHS Budget v. DHS Appropriations: Fact Sheet , by [author name scrubbed]. From FY2003 through FY2015, according to data from the Office of Management and Budget (OMB), the entire U.S. government spent almost $807 billion (in nominal dollars) on "homeland security"—defined in law as "those activities that detect, deter, protect against, and respond to terrorist attacks occurring within the United States and its territories." Such spending peaked in FY2009 at $73.8 billion. The OMB indicated that its initial estimate of the total budget for homeland security activities for FY2016 was $71.7 billion. By comparison, the budget for the Department of Homeland Security has grown from $31.2 billion in FY2003, when it did not have its own appropriations bill, to $63.5 billion in FY2015, the last year for which we have complete budget data as of the date of publication. Roughly $36.7 billion of that amount, or 57.8%, was considered "homeland security" spending by OMB's accounting under the above definition. Some argue that the definition in law is too focused on explicit and directly attributable counterterrorism activities compared to broader theories that have been part of the national discussion, which consider immigration and border control or disaster response as a part of homeland security. For FY2017, the Obama Administration requested $47.3 billion in discretionary budget authority for DHS, including over $6.7 billion to pay for the costs of major disasters under the Stafford Act. Additional Overseas Contingency Operations (OCO) funding was requested by the Administration for the Coast Guard as a transfer from the U.S. Navy. Neither the Senate bill nor the House bill that were reported out of their respective appropriations committees in response to that request received floor consideration. On September 29, 2016, President Obama signed P.L. 114-223 into law, which contained a continuing resolution that funded the government at the same rate of operations as FY2016, minus 0.496% through December 9, 2016. A second continuing resolution was signed into law on December 10, 2016 ( P.L. 114-254 ), funding the government at the same rate of operations as FY2016, minus 0.1901%, through April 28, 2017. A third continuing resolution extended funding at that rate through May 5, 2017. On March 16, 2017, the Trump Administration submitted an amendment to the FY2017 budget request. The amendment proposed $3 billion more in funding for DHS, including funding for construction of a border wall and increases in staffing for U.S. Customs and Border Protection and Immigration and Customs Enforcement that had been called for by President Trump in Executive Orders signed January 25, 2017. On May 5, 2017, President Trump signed into law P.L. 115-31 , Division F of which was the Department of Homeland Security Appropriations Act, 2017. The act included $49.3 billion in discretionary budget authority for DHS for FY2017, $1.1 billion of which was included as supplemental appropriations in response to the March request and emerging developments. The act included a finalized reorganization of most of the structure of DHS appropriations intended to improve transparency. However, the appropriations for the U.S. Coast Guard continue to be presented in their old structure due to complications with their financial management system. The current budget environment will likely present challenges to homeland security programs, DHS components, and the department as a whole, going forward. The funding demands of ongoing capital investment efforts, such as the proposed border wall and ongoing recapitalization efforts, and staffing needs for cybersecurity, border security, and immigration enforcement, will compete with one another for limited funding across the government and within DHS. The potential impact of the changing budget environment is discussed at various points throughout this report. [author name scrubbed], Research Fellow, Intelligence and National Security Policy ( [email address scrubbed] , [phone number scrubbed]) Heidi Peters, Research Librarian ( [email address scrubbed] , [phone number scrubbed]) While many think of homeland security only in terms of DHS, it is a primary mission of the entire Intelligence Community (IC). In the years since 9/11, the "wall" between foreign and domestic intelligence has fallen and many efforts have been initiated to better integrate the capabilities residing in intelligence and law enforcement organizations. "National intelligence" has come to mean "all intelligence," not just foreign intelligence. The many barriers between foreign and domestic intelligence that existed prior to 9/11 were intended to prevent government spying on U.S. persons and focused the IC on foreign intelligence. The tragedy of the 9/11 attacks overcame earlier concerns and led Congress and the executive branch to enact legislation, policies, and regulations designed to enhance information sharing across the U.S. government. The Homeland Security Act of 2002 ( P.L. 107-296 ) gave the DHS responsibility for fusing law enforcement and intelligence information relating to terrorist threats to the homeland. Provisions in the Intelligence Reform and Terrorist Prevention Act (IRTPA) of 2004 ( P.L. 108-458 ) established the National Counterterrorism Center (NCTC) as the coordinator at the federal level for terrorism information and assessment and created the position of Director of National Intelligence (DNI) to provide strategic management across the IC. New legal authorities accompanied these organizational changes. At the state and local level, initiatives to improve collaboration across the federal system, such as the FBI-led Joint Terrorism Task Forces (JTTFs), have expanded—the number of JTTFs across the country grew from 34 to over 100 between 2001 and 2017—and new ones, such as DHS's National Network of Fusion Centers (NNFC), have been put in place. The "community" of U.S. government entities that perform some kind of intelligence-related activity has gradually evolved into 17 organizations/agencies that span six separate government departments and two independent agencies. Two intelligence elements of DHS and one element of the FBI are most closely associated with homeland security. DHS's missions include "preventing terrorism and enhancing security; securing and managing our borders; enforcing and administering our immigration laws; strengthening cyberspace and critical infrastructure; and strengthening national preparedness and resilience to disasters."