Introduction
The United States Department of Homeland Security (DHS) was initially created to combat the growing threat of transnational terrorists. However, it now concerns itself with both domestic and transnational threat actors. The recent efforts to enforce immigration law have given DHS and other responding agencies a new set of challenges.
Efforts Against Terrorism
In recent years, homeland security itself has faced growing threats from terrorists and criminals who use dynamic, innovative methods and sophisticated tactics. According to a 2021 study, there were at least 230 unsuccessful domestic terrorist attacks or plots since 11 September 2001. Of those plots, 118 were committed by homegrown violent extremists (HVEs), 84 by domestic terrorists, and 28 by transnational terrorist organizations. The Center for Prevention Programs and Partnerships (CP3) was created within the DHS to identify and prevent radicalization.[1],[2],[3]
DHS has made several efforts to combat terrorism at the local, state, and federal levels. For example, Additionally, there are prevention forums in place to showcase tactics, techniques, and procedures (TTPs) used by terrorists, and how to prevent, mitigate, and respond to them. CP3 continues to work to highlight prevention resources that can be used to increase awareness of targeted violence. The program is also responsible for collaborating with international partners to advance terrorism prevention initiatives, thereby enhancing global engagement.[2]
Despite DHS’s efforts to bolster national security, there have still been recent terrorist attacks. On 01 January 2025 a man who self-identified with the Islamic State of Iraq and Syria (ISIS) drove his truck through Bourbon Street in New Orleans after strategically placing Improvised Explosive Devices (IEDs) around the area. The man struck and killed 14 people while injuring at least 57 others. Among those injured, were two (2) police officers who responded to the attack and were able to neutralize the attacker. According to New Orleans police, the barriers that would normally prohibit vehicles from entering the streets were not utilized due to recent malfunctions. Following the attack, a report from the Louisiana Governor’s Office of Homeland Security revealed that there may have been problems with some of the emergency alert systems put into place that . The report was used to analyze and identify issues in the response to the attack. The incident stood as a reminder that the terror threat to the U.S. is alive and persistent as transnational terrorist organizations continue to recruit Americans, some of whom self-radicalize via online propaganda and social media engagement. In the latter cases, the perpetrator may have had little or no contact with transnational terrorists but become radicalized over time before carrying out an attack.[1],[4],[5],[6],[7]
On 01 June 2025, an Egyptian national attacked a weekly march by pro-Israel activists campaigning for the release of hostages in Gaza. Using homemade Molotov cocktails and a makeshift flamethrower, he attacked the participants. While 12 attendees were injured, there were no fatalities. He had planned the attack for a year and expressed a desire to commit acts of antisemitic violence. He reportedly shouted “Free Palestine!” during the attack The suspect had overstayed a non-immigrant visa, which expired in February 2023, although he later applied for asylum. He has been charged with multiple felony counts and a federal hate crimes charge.[8]
The Rapidly Industrializing Threats to the Border
Rapidly advancing technology has created new threats along the U.S.-Mexico border. Drug cartels have used Unmanned Aerial Systems (UAS) to smuggle deadly narcotics into the U.S. According to Judicial Watch, drug cartels in one (1) year conducted at least 9,000 drone flights across U.S. airspace. Foreign nationals also used drones for intelligence.[9][10],[11]
In May 2024, authorities dismantled a smuggling operation after a year-and-a-half long investigation that resulted in charges against three (3) individuals. The suspects allegedly used a $630,000 drone to transport drugs between New York and Canada. U.S. Border Patrol agents tracked the drone’s flight path from New York to a winery in Ontario and, upon its return, recovered a package containing at least six (6) pounds of ecstasy. As of 01 April 2025, over one (1) million drones are registered within the United States. In response to these emerging threats (including drug smuggling at borders and in correctional facilities) U.S. Representatives Josh Riley and Zach Nunn introduced the “Stop Fentanyl Smuggling Act” on 29 April 2025. The proposed legislation aims to support the development of advanced detection technologies that would enable DoD personnel to identify and disrupt drug trafficking operations.[9],[12][13][14]
On 01 February 2025, officials received intelligence indicating Mexican cartel leaders authorized the use of drones equipped with explosives to be used against U.S. Border Patrol agents and Department of Defense (DoD) personnel along the U.S.-Mexico border. This report likely led to heightened security. As of 29 April 2025, the Pentagon is preparing to deploy counter-drone capabilities there due to threats made and in support of increased federal enforcement of immigration and security mandates. While tensions along the border have risen, DHS has acted to prevent and combat any attacks targeting DoD personnel and property. [15],[16]
Immigration at the Border
While history shows that Mexican nationals and individuals from other Central and South American countries have historically been the largest demographic groups encountered at the Southern Border, a dramatic increase in Chinese illegal immigration is on track to break records. FY22 reported an increase of more than 2,000 Chinese immigrants compared to FY21. FY23 reported a total of 24,314 Chinese immigrants. Furthermore, FY24 recorded 18,750 encounters by the end of January. The month of December 2024 recorded nearly 6,000 immigrants alone. Law enforcement officials working at the border have also reported illegal immigrants from more than 150 other countries.[17]
From 20 through 26 January 2025, there were 7,287 migrant encounters at the southern border. This number represents a 63% decrease after the Customs and Border Patrol (CBP) One app, which serves as a single portal to CBP services, was shut down. In addition to the CBP services provided, the app allowed immigrants to schedule appointments at different U.S. ports to enter into the country using humanitarian parole. In a sustained effort to secure the border, the U.S. recorded at least a 60% decrease in encounters between ports of entry along the southwest border from May 2024 to December 2024, the lowest it had been since August 2020. Under Title 8 of the U.S. Code, the DHS has legal authority to detain, process, or deport migrants who enter illegally. Migrants who cross the border illegally or arrive without proper documentation may be detained in detention facilities. These facilities are managed by the DHS and Immigration and Customs Enforcement (ICE). Additionally, in Arizona, there was a 30-foot wall that had gaps that hundreds of migrants would use daily to approach the Border Patrol. In 2024, the wall was completed, which stopped the flow of migrants from entering, leading to a significant decrease in immigrants at that port of entry.[18],[19],[20],[21]
In FY23, CBP reported 189,402 migrant encounters at the northern border. This number represented a 73% increase from 2022 and a 597% increase from FY21’s 27,180 migrant encounters. The Swanton Sector, which spans nearly 300 miles through eastern New York, Vermont, and New Hampshire, was responsible for more than two-thirds (2/3) of all reported apprehensions at the northern border during FY23. CBP agents at the northern border have reportedly expressed concerns about the U.S.-Canadian border being overlooked due to the threats at the U.S.-Mexico border. As a result, the potential for illegal border crossings at the northern border may have increased.[22],[23],[24]
Figure 1 – Migrant Encounters at the Northern Border FY22-FY25TD[24]
Figure 2 – Migrant Encounters at the Southern Border FY22-FY25TD24[24]
Outlook
Despite recent incidents, DHS has expanded its national security mission scope to include responding to natural disasters, thwarting terror plots on U.S. soil, and strengthening digital defenses to combat cyber adversaries, while collaborating with other agencies to tackle illegal immigration and border enforcement. As a result, DHS has become the third-largest cabinet department in the federal government. The threat to the country’s borders and to overall national security has been growing and evolving since the attacks on 11 September 2001. After the creation of DHS, the department has had to grow, advance, and evolve to safeguard the nation’s borders efficiently. While both domestic and transnational terrorists pose a threat to national security, other threat actors are enhancing their capabilities to disrupt DoD operations and jeopardize national security. Terrorists continue to illegally cross the nation’s borders while also recruiting and radicalizing individuals who are already on U.S. soil. Mexican cartels have advanced capabilities that allow them to remotely conduct surveillance operations and carry out lethal attacks along the border. Furthermore, migrants continue to approach U.S. borders with the hope of unlawfully entering the country. Recent data has shown that Chinese immigrants are accessing the borders more than ever before. The threat of espionage is obvious, and it demonstrates that Chinese intelligence entities leveraged the relaxed border enforcement of the previous four (4) years. The threat of cartels and their use of new and sophisticated technology at the border is present and ongoing. However, the influx of migrants from multiple countries from 2020 through 2024 may represent a latent threat of not only intelligence collection but kinetic attacks months, years, or even decades in the future.[25],[26]
[1] Dahl, E. (2021, November 07). Assessing the Effectiveness of the Department of Homeland Security, 20 Years After 9/11. Brown University. Retrieved from https://watson.brown.edu/costsofwar/files/cow/imce/papers/2021/Assessing%20DHS_Dahl_Costs%20of%20War.pdf.
[2] DHS. (n.d.). Partnerships and Engagement. DHS. Retrieved from https://www.dhs.gov/cp3/partnerships-and-engagement.
[3] CP3. (n.d.). Targeted violence and terrorism are preventable. DHS. Retrieved from https://www.dhs.gov/sites/default/files/2025-01/2025_0129_cp3-overview.pdf.
[4] Lowrey, E. (2025 January 29). New Orleans terror attack response riddled with issues highlighted in after-action report. WDSU. Retrieved from https://www.wdsu.com/article/new-orleans-terror-attack-response-action-report/63609441.
[5] Homeland House. (2025, January 22). House Homeland Releases Updated “Terror Threat Snapshot” Assessment in Wake of New Year’s Day ISIS-Inspired Terrorist Attack in New Orleans. Homeland House. Retrieved from https://homeland.house.gov/2025/01/22/house-homeland-releases-updated-terror-threat-snapshot-assessment-in-wake-of-new-years-day-isis-inspired-terrorist-attack-in-new-orleans/.
[6] FBI. (2025, January 14). Bourbon Street Attack Investigation Updates. FBI. Retrieved from https://www.fbi.gov/news/press-releases/bourbon-street-attack-investigation-updates.
[7] Adelson, J. (2025, January 07). Attacker drove down 3 blocks of Bourbon Street with no barriers. How did that happen?. Retrieved from https://archive.ph/4gwOW#selection-3925.0-3925.85.
[8] Haubner, A., Milton, P., & Swanson, C. (2025, June 2). Attack in Boulder, Colorado, burns 12 people at march for Israeli hostages, officials say; suspect charged. CBS News Colorado. Retrieved from https://www.cbsnews.com/colorado/news/colorado-police-responding-to-boulder-pearl-street-mall-attack-multiple-injured/.
[9] Edward, B. (2025, May 02). Drones Smuggling Deadly Drugs Across U.S. Borders, Report Reveals. Digital Chew. Retrieved from https://digitalchew.com/2025/05/02/drones-smuggling-deadly-drugs-across-u-s-borders-report-reveals/.
[10] AXON. (2025, February 07). Countering cartel drone threats: How CUAS systems can protect U.S. Border Patrol Agents. AXON. Retrieved from https://www.axon.com/blog/countering-cartel-drone-threats.
[11] Suarez, K. (2021, June 02). Drug cartels attack enemies and spread terror with weaponized drones in US, Mexico. USA Today. Retrieved from https://www.usatoday.com/story/news/nation/2021/06/02/mexican-drug-lords-use-drones-spread-terror/7506312002/.
[12] AP News. (2024, May 16). Drones smuggled drugs across Niagara River from Canada, 3 suspects caught in NY. AP News. Retrieved from https://apnews.com/article/drone-drug-smuggling-niagara-new-york-426468e8cc99bae3531ff2ac3a404043.
[13] Federal Aviation Administration. (2025, April 01). Drones. FAA. Retrieved from https://www.faa.gov/uas.
[14] House. (2025, April 29). Rep. Riley Introduces Bipartisan Bill to Crack Down on Fentanyl Smuggling at Border and in Prisons. House. Retrieved from https://riley.house.gov/media/press-releases/rep-riley-introduces-bipartisan-bill-crack-down-fentanyl-smuggling-border-and.
[15] Fitz-Gibbon, J., & Taer, J. (2025, February 3). Mexican drug cartels plan attacks on Border Patrol agents with kamikaze drones and other explosives to fight US crackdown. New York Post. Retrieved from https://nypost.com/2025/02/03/us-news/mexican-cartels-order-suicide-drone-attacks-on-border-patrol/.
[16] Vincent, B. (2025, April 29). DOD to deploy counter-drone capabilities at US-Mexico border as cartels surveil troops. Defense Scoop. Retrieved from https://defensescoop.com/2025/04/29/dod-counter-small-drones-u-s-mexico-border-cartels-surveil-troops/.
[17] Hopkins, J. (2024, February). Record Number Of Chinese Nationals Illegally Crossing Into US, Latest Data Shows. MSN. Retrieved from https://www.msn.com/en-us/news/us/record-number-of-chinese-nationals-illegally-crossing-into-us-latest-data-shows/ar-BB1mwdSm?ocid=BingNewsVerp.
[18] Shaw, A. (2025, January 28). Trump-era southern border sees migrant encounters plummet by over 60% as new policies kick in. Fox News. Retrieved from https://www.foxnews.com/politics/trump-era-southern-border-sees-migrant-encounters-plummet-over-60-new-policies-kick-in.
[19] ICE. (n.d.). Detention Management. ICE. Retrieved from https://www.ice.gov/detain/detention-management.
[20] House. (n.d.). Title 8—Aliens And Nationality. House. Retrieved from https://uscode.house.gov/view.xhtml?req=granuleid%3AUSC-prelim-title8&edition=prelim.
[21] Lapidus, S. (2025, 09 May). US wants migrants to know that crossing the border illegally could mean jail time. AZ Central. Retrieved from https://www.azcentral.com/story/news/politics/border-issues/2025/05/09/us-officials-warn-migrants-not-to-cross-border-illegally/83522227007/.
[22] Robinson, M. (2024, May 31). Migrant Encounters at US-Canada Border Rise More Than 1,000% in 3 Years. Newsweek. Retrieved from https://www.newsweek.com/us-migrant-crisis-encounters-rise-over-1000-percent-northern-border-three-years-1906786?.
[23] Chapman, C. (2024, August 19). Northern border communities see a dramatic increase in unauthorized migrant crossings. KCSM. Retrieved from https://www.kcsm.org/npr-news/2024-08-19/northern-border-communities-see-a-dramatic-increase-in-unauthorized-migrant-crossings.
[24] CBP. (12 May 2025). Nationwide Encounters. CBP. Retrieved from https://www.cbp.gov/newsroom/stats/nationwide-encounters.
[25] Warwick, T. (2021, September 13). State of DHS: 20 Years After 9/11, Which Way Forward?. HS Today. Retrieved from https://www.hstoday.us/featured/state-of-dhs-20-years-after-9-11-which-way-forward/.
[26] Jingnan. H. (2024, August 09) What drove last year’s surge in Chinese migrants at the southern border?. NPR. Retrieved from https://www.npr.org/2024/08/07/nx-s1-5032835/chinese-migrants-southern-border.
