WASHINGTON (Reuters) - The U.S. Supreme Court is set to consider a major cellphone privacy case later this month, but leading players in the wireless industry that is at the center of the closely watched dispute are keeping their distance.

FILE PHOTO: The Verizon logo is seen on the side of a truck in New York City, U.S., October 13, 2016. REUTERS/Brendan McDermid/File Photo

The case, to be heard by the justices on Nov. 29, involves whether a warrant is required for authorities to obtain cellphone location information that could implicate criminal suspects, the latest in a string of Supreme Court cases on privacy rights in the digital age.

It has become the latest example of how American phone carriers have been reluctant to engage in data privacy disputes -- especially those that may pit them against the U.S. government -- despite their role as custodians of customer data, legal experts and privacy advocates say.

Of the four major U.S. mobile phone carriers -- Verizon Communications Inc, AT&T Inc, Sprint Corp and T-Mobile US Inc -- only Verizon has taken a stand in the case. Verizon joined a legal brief with technology companies including Alphabet Inc’s Google and Apple Inc calling for stronger protections for the privacy of customer data.

Wireless industry trade group CTIA has shied away from the case, the most significant in years on phone privacy.

Digital right advocates have criticized the industry’s hands-off approach.

“Few private actors have been more involved in the erosion of Americans’ privacy than the telecoms, particularly over the last 15 years,” said Alex Abdo, a senior staff attorney at the Knight First Amendment Institute at Columbia University in New York, which filed a brief supporting expanded privacy rights in the case. “They have been silent for almost all that time.”

Despite massive growth in the amount and types of customer data stored by phone and tech companies, U.S. law on how to treat that information has barely changed during that period.

Some tech firms have urged reforms that would ensure privacy protections for customer data. Microsoft and Google both opposed the government’s attempts to obtain customer data stored on foreign servers, a central issue in the other major tech case currently before the Supreme Court.

CTIA, AT&T and T-Mobile declined to comment on the current case. Sprint spokeswoman Lisa Belot said the company had not taken a position on it.

Verizon spokesman Rich Young said the case “highlights the ever-existing need to find the right balance between law enforcement and privacy, and raises tough questions about how to apply old statutes and legal doctrines to modern technologies.”

Although the legal fight is about location information, “the Supreme Court’s decision is likely to impact how the government obtains other sensitive types of information from many other types of providers,” Young added.

UNREASONABLE SEARCH

The Supreme Court twice in recent years has ruled on how criminal law applies to new technology, both times ruling against law enforcement authorities.

Cellphone location records are becoming increasingly important in criminal investigations, with authorities routinely requesting and receiving this data from wireless providers. The four major wireless carriers handle thousands of requests from law enforcement annually for this data.

Such data shows which local cellphone towers that phone users connected to when they made calls. Police can use past data to determine if a suspect was in the vicinity of a crime.

The justices will hear an appeal by a man named Timothy Carpenter who was convicted in armed robberies in Ohio and Michigan. Police helped establish Carpenter was near the scene of robberies at Radio Shack and T-Mobile stores by securing past cell site location information from his cellphone carrier, MetroPCS, now owned by T-Mobile.

Carpenter’s American Civil Liberties Union lawyers argued that police need “probable cause,” and therefore a warrant, in light of the U.S. Constitution’s Fourth Amendment protections against unreasonable searches.

Based on a provision of a 1986 law called the Stored Communications Act, the Justice Department said probable cause was not needed, but rather the lesser “reasonable grounds,” to show that records are “relevant and material” to an investigation.

Civil liberties groups said that law did not anticipate the way mobile devices would become huge data depositories.

A ruling favoring Carpenter would set a precedent that could be applied to other forms of data. Investigations on a range of issues, including public corruption and identity theft, would be threatened if Carpenter wins, the National District Attorneys Association said in a legal brief.

Unlike internet firms, telephone providers require government licenses to operate and many have signed contractual agreements that mandate cooperation with the government on legal processes, said Albert Gidari, a lawyer who represented phone and internet companies on surveillance issues for 20 years.

Digital rights activists said this fact makes U.S. carriers reluctant to pick privacy fights with the government.

“On these issues,” Gidari said, “it does not serve them to be very vocal.”