Under federal law, government agents are authorized to “interrogate any alien or person believed to be an alien as to his right to be or to remain in the United States.” Under applicable regulations, the agents “may briefly detain” an individual “for questioning” if they have “a reasonable suspicion, based on specific articulable facts, that the person being questioned . . . is an alien illegally in the United States.”

In June 2025, agents from the Immigration and Customs Enforcement division of the United States Department of Homeland Security were deployed throughout Los Angeles to arrest undocumented immigrants as part of a plan called “Operation At Large,” which “federal officials have described as ‘the Largest Mass Deportation Operation . . . in History.’” Five individuals stopped during Operation At Large and four interested associations challenged the constitutionality of the agents’ tactics, filing a class action against Secretary of Homeland Security Kristi Noem and other immigration officials.

In July, a federal district court in California entered a temporary restraining order (TRO) enjoining the government from basing reasonable suspicion for a stop “solely” on certain factors, whether “alone or in combination”:

1. “Apparent race or ethnicity;”
2. “Speaking Spanish or speaking English with an accent;”
3. “Presence at a particular location (e.g., bus stop, car wash, tow yard, day laborer pick up site, agricultural site, etc.);” or
4. “The type of work one does.” 

On September 8, the Supreme Court granted defendants’ application for a stay of the TRO pending appeal in the Ninth Circuit. Justice Brett Kavanaugh, concurring in the grant of the stay, wrote that it is “common sense” that in the Los Angeles area, the factors on which the district court’s TRO enjoined the government from relying can, taken together, “constitute at least reasonable suspicion of illegal presence in the United States.” Justice Kavanaugh noted that under the Court’s precedent, “apparent ethnicity” is not alone enough to create reasonable suspicion but can contribute to the formation of reasonable suspicion “when considered along with other salient factors.”

In weighing the balance of harms and equities, Justice Kavanaugh stated that the interests of those in the country illegally in avoiding interrogation or detention is “not . . . especially weighty,” and opined that when individuals legally in the U.S. are stopped by immigration officials, questioning “is typically brief, and those individuals may promptly go free after,” clarifying that they are either U.S. citizens or otherwise legally present in the country. Writing on behalf of the dissenting justices, Justice Sonia Sotomayor deemed the harm to U.S. citizens and documented immigrants significantly greater than Justice Kavanaugh’s concurrence recognized and argued that the Court’s decision removes Fourth Amendment protection from “arbitrary interference by law officers” for individuals with a certain appearance and manner of speech who are employed in certain low-wage jobs.

Even though Perdomo is not a merits opinion, it may foreshadow how the Court will ultimately rule on this issue. At a minimum, it foretells a loosening of the reasonable suspicion standard in the context of immigration stops. The concurrence allows immigration agents to meet that standard based on “specific articulable facts” which previously would likely have been deemed insufficient and potentially characterized as racial profiling.

Although Perdomo did not arise out of a worksite enforcement operation, companies operating in industries where employees of foreign descent are common should be mindful of the ruling. Even when those agents are onsite pursuant to a search warrant or consent, before Perdomo they were obligated to identify “specific articulable facts” demonstrating reasonable suspicion before detaining and questioning individual employees. Perdomo lowers the applicable standard, effectively empowering immigration agents to detain and question any employee onsite who meets the criteria listed in the concurrence — though it is unclear how many of the four listed factors must be present to create reasonable suspicion under the “totality of the circumstances.”

In this new environment, we recommend companies consider the following steps:

• Develop a response plan for unannounced visits by government agents. Senior officials onsite and those employees most likely to interact with those agents initially should be trained on how to respond.
• Evaluate the areas of greatest risk and adjust policies accordingly. For example, temporary staffing agencies are often a source of undocumented workers. Companies should work to ensure that individuals provided by such agencies are properly documented and terminate relationships with agencies who demonstrate insufficient attention to detail in this area.
• Employees should be strongly encouraged, if not required, to carry identification and/or documentation demonstrating that they are in the country legally and are authorized to work. This requirement should apply to all employees, including subcontractors and even those individuals born in the United States. Because Perdomo validates detention and questioning based on an individual’s “apparent race or ethnicity” coupled with a factor such as “the type of work one does,” even those individuals born in the United States are subject to detention and questioning if they appear to be of foreign descent and are working certain jobs (such as agriculture, construction, or assembly line work).
• Where feasible, companies should separately maintain identification information for employees, and strongly encourage subcontractors to do the same. Having such information readily at hand can serve to reduce the disorder and disruption that might otherwise result from an unannounced visit.

Listen to this post