The government has a unique interest in policing its borders, and people have a lower reasonable expectation of privacy where borders are involved. In general, officials have more search-and-seizure leeway at and around the border.
The U.S. Border Patrol—an arm of Customs and Border Protection (CBP)—monitors and enforces border security, customs, and immigration law at more than 300 ports of entry (land, air, and sea). It's also authorized to operate within 100 miles of the border. Border patrol or CBP agents have greater authority to seize, search, and detain individuals at and near the border than law enforcement officers have in other circumstances. Their authority, though, is limited to enforcing immigration and federal laws.
At ports of entry, the Supreme Court has decided that the government's interest in maintaining border security trumps an individual's privacy interests. By simply being at the border (or its functional equivalent, like an international airport), agents can conduct "routine" questioning and searches at random and without a warrant, consent, probable cause, or reasonable suspicion of criminal activity. For "non-routine" searches, agents must have reasonable suspicion of criminal activity (still a low standard). This expanded authority is referred to as the "border-search exception." (U.S. v. Ramsey, 431 U.S. 606 (1977), citing Carroll v. U.S., 267 U.S. 132 (1925).)
Border Patrol also operates within 100 miles of the U.S. border through roving patrols and interior immigration checkpoints. Roving patrols can pull over vehicles for suspected immigration violations. At interior checkpoints, anyone passing through may be stopped for immigration inquiries, even if they haven't crossed the border.
Although persons have greater privacy interests within the 100-mile border zone than at the border, Fourth Amendment protections are still reduced and impact anyone present in the zone (not just those entering the country). These reduced protections—applicable to two-thirds of the U.S. population living there—have led to this zone being dubbed the "Constitution-Free Zone."
Outside the border context, a law enforcement officer generally needs reasonable suspicion of criminal activity to detain a person and probable cause to arrest someone. Searches can only be conducted if the officer has a probable cause warrant from a judge or an exception to the warrant requirement exists.
Below we dive into these border stops and searches in more depth.
Border patrol has the greatest authority to question, detain, and search persons at border crossings and other ports of entry (seaports and international airports).
When entering the United States by land, air, or sea, border patrol agents can stop and ask you questions regarding your citizenship and what you are bringing into the country. Agents don't need to suspect any criminal activity. They may inspect your passport, visa, and any other entry documents. The amount of time to conduct these questions should be brief. Repeat or lengthier detentions generally require reasonable suspicion. (Carroll v. U.S., 267 U.S. 132 (1925).)
Agents also don't need a warrant or even reasonable suspicion to search you and your belongings at border crossings or ports of entry. Border patrol agents may conduct a routine search of your outer clothing, personal effects, pockets, wallet, and bags without cause. (U.S. v. Martinez-Fuerte, 428 U.S. 543 (1976).) Canine sniffs of your person are also considered a routine search. (U.S. v. Tenorio, 55 F.4th 465 (5th Cir. 2022).) Strip searches, however, do not fall under the definition of routine search. (U.S. v. Montoya de Hernandez, 473 U.S. 531 (1985).)
Your vehicle isn't off limits either. Border patrol agents may conduct warrantless searches of your vehicle at border crossings, including your vehicle's interior and any personal belongings found inside. This unfettered permission went as far as dismantling a gas tank in one case. (U.S. v. Flores-Montano, 541 U.S. 149 (2004).)
Although the rules are less clear on searches of cellphones and digital devices, courts have upheld manual searches of such devices by CBP agents without a warrant, consent, or any suspicion of criminal activity. However, some courts have limited the extent of this search by holding that a forensic digital search requires reasonable suspicion of criminal activity. (U.S. v. Saboonchi, 990 F.Supp.2d 536 (D. Md. 2014).)
Suspicionless stops at immigration checkpoints are allowed but must be limited in scope and duration. Officers at immigration checkpoints (those removed from the border) may briefly stop vehicles and ask passengers questions limited to immigration. Agents should not ask questions unrelated to residency or citizenship. They can briefly detain you to verify your immigration status. (U.S. v. Martinez-Fuerte, 428 U.S. 543 (1976).)
Border patrol agents may conduct a visual inspection of the exterior of your vehicle. Canine sniffs of the exterior are also allowed. (U.S. v. Hernandez, 976 F.2d 929 (5th Cir. 1992).) At busy checkpoints, an agent can send you and your vehicle to a secondary inspection but only for the same limited purposes.
Agents cannot search the inside of your car unless they have your consent (which you don't need to give) or probable cause of an immigration violation or criminal activity. They cannot search cars at random. (U.S. v. Ortiz, 422 US. 891 (1975); U.S. v. Machuca-Barrera, 261 F.3d 425 (5th Cir. 2001).)
No, roving patrols can pull over vehicles only where an immigration crime is suspected. While random stops are not permitted, officers only need reasonable suspicion that illegal aliens may be in the car.
An officer's reasonable suspicion may be based on:
The agent can also consider the driver's behavior, any obvious aspects of the vehicle (such as a vehicle carrying a heavier load than the passengers would indicate), and the number and behavior of passengers. (U.S. v. Brignoni-Ponce, 422 U.S. 873 (1975).)
Like immigration checkpoints, roving patrol officers cannot search you or your vehicle without consent or probable cause of an immigration violation or criminal activity. (Almeida-Sanchez v. U.S., 413 U.S. 266 (1973).)
The authority granted to Border Patrol within the 100-mile border zone authorizes agents to board buses and trains. They might board a bus or train at a stop or even en route to ask passengers questions about immigration status and to show documents. (U.S. v. Portillo-Aguirre, 311 F.3d 647 (5th Cir. 2002); U.S. v. Sanchez, 569 F.Supp.1129 (D.N.M. 2021).) To detain you longer, they will need reasonable suspicion of wrongdoing. Probable cause is needed to arrest or search you or your belongings. (Bond v. U.S., 529 U.S. 334 (2000).)
If you've been arrested or charged with a crime based on a border patrol stop or search, contact a criminal defense attorney or ask for a lawyer before answering additional officer questions.