Arguing that Greyhound is misinterpreting a federal law on immigration status checks that take place at a distance from international borders, the American Civil Liberties Union is urging the bus company to stop federal agents from boarding its buses and making arrests.

Ten ACLU affiliates, including New York State's chapter, recently sent an open letter to Greyhound arguing that the company has a Fourth Amendment right to deny Customs and Border Protection agents access to its buses and that, to ensure the constitutional rights of its passengers, it must. Unless the agents have a judge-issued warrant, they shouldn't be there, according to the ACLU.

While immigration checks on Greyhound buses and Amtrak trains have reportedly taken place for years, the ACLU letter was prompted, the organization said, by a stream of recent Greyhound incidents that have occurred as the Trump administration cracks down on illegal immigration.

The bus company's public response has been to state, as it did in January, that “we are required to comply with all local, state and federal laws and to cooperate with the relevant enforcement agencies if they ask to board our buses or enter stations.”

But the ACLU, in its fervent letter replete with U.S. Supreme Court case law addressing the primacy of the U.S. Constitution, contends that Greyhound simply has the law wrong and must change its policy.

“Neither statutes nor regulations can override a business's Fourth Amendment right to refuse consent to enter nonpublic areas under its control,” the ACLU writes in the five-page letter, which was signed by executive and legal directors from 10 border-state chapters found across the country.

The letter, dated March 21, also states that “a ticket is required to board a bus, and therefore the public may not come and board a bus at will. Accordingly, law enforcement officers must generally have a warrant, probable cause, or consent to board a bus.”

The letter includes two pages of examples, from seven different border states, of incidents in which it says border patrol agents have misused their authority to intimidate or, at times, take into custody Greyhound passengers. Citing about a dozen news reports, it also says that CBP has a “practice of boarding Greyhound buses without even any pretense of suspicion and detaining passengers until they answer questions about their citizenship and immigration status and present immigration documentation.” Moreover, the ACLU writes, “CBP often singles out individuals because of the color of their skin or because they have a foreign accent. [And] in a number of reported cases, CBP agents arrested individuals on Greyhound buses without probable cause to believe they were deportable.”

But Greyhound, as well as the CBP agency itself, have cited laws and regulations found in the Immigration and Nationality Act that they say grant federal agents broad authority to search people suspected of immigration violations, even when they're not near a land or maritime border, as long as the suspects are within a “reasonable distance” to a border of 100 miles or less.

So far that interpretation has carried the day. To date, the national bus carrier has not announced any change to its practice of allowing federal border patrol agents to climb aboard its vehicles to question passengers or demand documents.

In an email Monday, Lanesha Gipson, a Greyhound Lines spokeswoman, said, “We understand the ACLU's concerns and those of our customers with regard to this matter. However, Greyhound is required to comply with the law.” She added that “Greyhound has opened a dialogue with the Border Patrol to see if there is anything that can be done to balance the enforcement of federal law with the dignity and privacy of our valued customers.”

She also listed numerous provisions found in the INA and its corresponding regulations, including 8 U.S.C. §1357(a)(3), which says, in part, that immigration authorities “shall have power without warrant, within a reasonable distance from any external boundary of the United States, to board and search for aliens any … vehicle … for the purpose of patrolling the border to prevent the illegal entry of aliens into the United States.”

Still, the ACLU, in its letter, attacks that provision head-on.

It quotes from the provision and states, “however, as the Supreme Court has made clear, 'no Act of Congress can authorize a violation of the Constitution,'” quoting Almeida-Sanchez, 413 U.S. 266, 272, which the civil rights group describes as barring the border patrol's warrantless search of a car without probable cause or consent despite the language of §1357. Moreover, the ACLU writes that “the same is true for agency regulations,” quoting United States v. Brignoni-Ponce, 422 U.S. 873, 883 (1975), which the ACLU says rejected the position that any statute and regulation allows the border patrol to “stop motorists at random for questioning, day or night, anywhere within 100 air miles of the 2,000-mile border … without any reason to suspect that they have violated any law.”

“Greyhound is in the business of transporting its passengers safely from place to place,” the civil rights group says, adding, “It should not be in the business of subjecting its passengers to intimidating interrogations, suspicionless searches, warrantless arrests, and the threat of deportation.”

David Long, a CBP spokesman based in Buffalo, said in an email Monday that “for decades, the U.S. Border Patrol has been performing enforcement actions away from the immediate border in direct support of border enforcement efforts and as a means of preventing trafficking, smuggling and other criminal organizations from exploiting our public and private transportation infrastructure to travel to the interior of the United States.”

He added that “although most Border Patrol work is conducted in the immediate border area, agents have broad law enforcement authorities and are not limited to a specific geography within the United States,” and he cited the INA §287(a)(3) and 8 U.S.C. §1357.

Naomi Dann, an NYCLU spokeswoman, said by email that the “ACLU is continuing to engage with Greyhound on the issue” raised in the March letter. Asked if the group had plans to bring litigation in regard to the CBP's enforcement actions on buses, she said she had no “details currently” on any such plans.