The Department of Homeland Security

CBP is the largest federal law enforcement agency in the country, responsible for securing the nation's borders and staffing official ports of entry, screening both people and cargo entering the United States while also collecting import duties and enforcing customs and agricultural regulations.

The agency operates along both the northern and southern land borders as well as international airports and seaports nationwide, and its Border Patrol component, which handles areas between official ports of entry, has grown substantially in staffing and funding as immigration enforcement has become an increasingly central national political issue.

CBP has about 65,000 employees, including roughly 20,000 Border Patrol agents and 25,000 officers at the roughly 330 air, land, and sea ports of entry, where more than a million people and hundreds of billions of dollars in goods cross legally each day. It also collects tariffs, a revenue source that grew sharply in 2025, though still well behind individual income and payroll taxes.

The Border Patrol's authority to operate "within a reasonable distance" of the border has long been set by regulation at 100 air miles, a zone that includes about two-thirds of the U.S. population and where agents can run checkpoints and, with limits, board buses and trains. CBP also runs an air and marine arm with drones, helicopters, and boats.

ICE enforces immigration law within the interior of the United States, identifying, arresting, detaining, and removing individuals who are in the country unlawfully, and separately investigates transnational crime including human trafficking, drug smuggling, and financial crimes through its Homeland Security Investigations division.

ICE has become one of the most politically contested agencies in the federal government in recent years, drawing both strong support and strong opposition over its enforcement practices, detention conditions, and the scope of interior immigration operations, with funding for the agency significantly expanded under recent legislation.

ICE has two main arms: Enforcement and Removal Operations, which makes arrests and runs a detention system that has held on the order of 30,000 to 50,000 people a day in a nationwide network of mostly contracted facilities, and Homeland Security Investigations, a large criminal-investigation agency whose work extends well beyond immigration to cybercrime, art theft, and trade fraud.

The agency's priorities shift sharply between administrations: some have focused enforcement on people with serious criminal records, others on broad interior enforcement including at courthouses and workplaces. Detention capacity, the use of local jails under "287(g)" agreements, and the treatment of people held in custody are recurring subjects of litigation and inspector-general reports.

TSA screens passengers and baggage at commercial airports nationwide, a function created after the September 11 attacks federalized what had previously been private airport security screening, and also has a role in securing other transportation modes including rail and mass transit systems.

TSA screens roughly 2.5 million airline passengers daily across more than 400 U.S. airports, and its screening procedures, from liquid restrictions to full-body scanners, have periodically drawn both public criticism over convenience and traveler privacy, as well as ongoing scrutiny over their actual effectiveness at detecting threats.

TSA has about 60,000 employees, most of them screening officers, and its budget is partly funded by a per-ticket "September 11 security fee." Internal covert tests by the DHS Inspector General have repeatedly found that undercover agents were able to smuggle mock weapons or explosives past checkpoints a large share of the time, prompting equipment and training changes.

Beyond aviation, TSA writes security rules for freight rail, pipelines, and mass transit, mostly through requirements on the private operators, and it runs the Federal Air Marshal Service. Its screening workforce was long paid on a separate, lower pay scale than the rest of the federal government until Congress moved it onto the standard system in the mid-2020s.

FEMA coordinates the federal response to natural disasters and other large-scale emergencies, providing direct financial assistance to disaster survivors, funding state and local emergency response capabilities, and managing the National Flood Insurance Program, which covers flood risk that most standard homeowner policies exclude.

FEMA's response is triggered when a governor requests and the president approves a federal disaster declaration, and the agency's performance has swung between widely praised responses and heavily criticized failures across different disasters, most notably its widely criticized response to Hurricane Katrina in 2005.

FEMA is comparatively small, a few thousand permanent staff plus a large reserve corps activated for disasters, and it works mostly through money: it reimburses states and localities for most emergency and rebuilding costs and pays survivors capped grants for temporary housing and repairs. It is deliberately a coordinator, not a first responder; local and state agencies lead, and FEMA supports.

The National Flood Insurance Program, which FEMA runs, covers most U.S. flood policies but has borrowed tens of billions of dollars from the Treasury it cannot repay after catastrophic storms, and Congress has kept it alive through dozens of short-term reauthorizations while debating how to price flood risk in a changing climate.

Katrina remains the most consequential disaster response failure in DHS's history, with widely documented delays in FEMA's assistance, breakdowns in coordination between federal, state, and local officials, and images of stranded survivors that drew intense national and international criticism of the response.

The disaster prompted lasting institutional reforms and remains the standard reference point whenever DHS's disaster response capabilities face renewed scrutiny during subsequent major hurricanes or emergencies.

The failures were shared across all levels of government: the New Orleans levees, built and maintained by the Army Corps of Engineers, failed in more than 50 places; the state and city evacuation and sheltering plans broke down; and FEMA director Michael Brown, who had limited emergency-management experience, was removed from the response within two weeks and resigned days later.

Congress's bipartisan House investigation was titled "A Failure of Initiative." The lessons, pre-positioning supplies, pre-scripted mission assignments, and a stronger FEMA administrator, were credited with markedly better federal responses to later storms such as Hurricanes Gustav (2008) and Sandy (2012), though large disasters continued to expose gaps.

In January 2017, DHS designated U.S. election systems as 'critical infrastructure,' formally extending federal cybersecurity support and coordination to state and local election officials following documented Russian government attempts to probe state voter registration systems during the 2016 election.

The designation, made in the final days of the Obama administration, was controversial among some state officials who viewed it as federal overreach into a traditionally state-controlled function, but it has become a lasting and largely accepted part of how election infrastructure security is now coordinated nationally.

The designation is voluntary for states: it makes DHS help available (network scans, threat briefings, an information-sharing center for election officials) but gives the federal government no authority over how elections are run. By 2020 nearly every state and thousands of local jurisdictions had joined the Election Infrastructure Information Sharing and Analysis Center.

CISA officials publicly called the 2020 election "the most secure in American history" and found no evidence of altered votes, a statement that led to the firing of CISA's director. The agency scaled back its work flagging election misinformation to social media companies after lawsuits and a 2023 court injunction that the Supreme Court later reversed for lack of standing in Murthy v. Missouri (2024).

Secretary Kristi Noem departed in early 2026 following high-profile congressional scrutiny over immigration enforcement operations, including the deaths of two U.S. citizens during operations in Minnesota, and department spending decisions, becoming the first Cabinet-level departure of the second Trump administration.

Markwayne Mullin's subsequent confirmation as her successor in March 2026 came amid a broader wave of Cabinet turnover across the administration that year, with DHS, Justice, and Labor all seeing new leadership within a matter of months.

The Minnesota operations that drew scrutiny were part of an expanded interior-enforcement effort in 2025 and 2026; the incidents remained under review by the department's inspector general and, in one case, by the Justice Department, and this page describes them only as documented use-of-force events that shaped the political debate over the department, without assigning fault.

Cabinet turnover of this scale early in a term is unusual, and Senate confirmation of a sitting senator to run a department that a member of his own party's chamber had been investigating was itself a point of debate during the March 2026 hearings.

CBP administers trusted traveler programs like Global Entry and TSA PreCheck, which allow pre-vetted, low-risk travelers to move through expedited security and customs screening at airports, reducing wait times for enrolled travelers while allowing the department to focus more intensive screening resources on unknown or higher-risk travelers.

These programs have grown to cover tens of millions of enrolled travelers and are widely viewed as one of the department's more successful risk-based security initiatives, balancing security screening needs against the practical realities of a high-volume international travel system.

PreCheck (run by TSA) covers domestic airport screening and lets members keep on shoes, belts, and light jackets; Global Entry (run by CBP) adds an expedited customs kiosk for international arrivals and includes PreCheck. Both require a background check, fingerprints, and an in-person interview, and cost a modest fee for five years, often reimbursed by credit cards and employers.

CBP also runs land-border trusted-traveler lanes (NEXUS with Canada, SENTRI with Mexico) and the Mobile Passport and facial-comparison systems now used at many airports, part of a long-planned biometric entry-exit program Congress first mandated in 1996.

FEMA's Individual Assistance program provides direct financial help to disaster survivors for temporary housing, home repairs, and other disaster-related expenses, while its Public Assistance program reimburses state and local governments for emergency response costs and infrastructure repair after a federally declared disaster.

These programs have paid out tens of billions of dollars in the years following major hurricanes, wildfires, and other disasters, and eligibility and payout speed remain a recurring subject of both praise and criticism depending on the specific disaster and community affected.

Individual Assistance grants are capped (in the low tens of thousands of dollars per household) and are meant to make a home safe and habitable, not to restore it fully, and survivors are pointed to Small Business Administration disaster loans and insurance for the rest. FEMA reworked the program in 2024 to simplify applications after studies and lawsuits found lower-income and minority applicants were denied at higher rates.

Public Assistance, which covers the government's own costs, is the larger program, and after big disasters it can fund rebuilding for years; FEMA typically pays at least 75 percent, with the state and locality covering the rest. Roughly 60 to 130 major disaster declarations are issued in a typical year, and the Disaster Relief Fund that pays for them periodically runs low and requires emergency appropriations from Congress.

CISA works with private companies that operate power grids, water systems, financial networks, and other critical infrastructure to share threat intelligence and help defend against cyberattacks, since the majority of U.S. critical infrastructure is privately owned rather than directly controlled by the federal government.

The agency has played an increasingly central role in responding to major ransomware attacks against infrastructure operators, including the 2021 Colonial Pipeline attack that disrupted fuel supplies across the East Coast, helping coordinate both the immediate response and longer-term infrastructure hardening efforts.

The government recognizes 16 critical-infrastructure sectors, from energy and water to health care and elections. CISA runs the federal .gov network's intrusion-detection system, issues binding directives to agencies to fix known-exploited flaws, publishes advisories on industrial control systems, and staffs regional cybersecurity advisers who offer free scans and exercises to states and companies.

The 2022 Cyber Incident Reporting for Critical Infrastructure Act, still being written into regulation, will for the first time require critical-infrastructure operators to report significant cyberattacks and ransom payments to CISA within days, giving the government a fuller picture of a threat that is now overwhelmingly criminal and often based overseas.

The Secret Service protects the president, vice president, their families, and other senior officials and visiting foreign dignitaries, and separately investigates financial crimes including counterfeiting and certain types of fraud, a dual law enforcement and financial crimes mission dating back to the agency's 1865 founding.

The agency's protective mission has faced periodic high-profile scrutiny following security lapses, prompting internal reforms and congressional oversight hearings aimed at strengthening protocols around presidential and vice-presidential security.

The Secret Service was created to fight rampant counterfeiting after the Civil War, when as much as a third of circulating currency was fake, and only took on full-time presidential protection after William McKinley became the third president assassinated, in 1901. It moved from the Treasury to DHS in 2003 but kept its financial-crimes work, which now centers on cybercrime and payment fraud.

Recent lapses have included a 2014 White House fence-jumper who reached the East Room, a 2011 shooting at the residence that went unnoticed for days, and the July 2024 attempt on Donald Trump's life at a Pennsylvania rally, after which the director resigned and an independent panel found "deep flaws" in planning and coordination. The agency also secures designated "National Special Security Events" such as inaugurations, state funerals, and the UN General Assembly.