After a federal court ordered Apple to help unlock an iPhone used by an attacker in a December mass shooting in San Bernardino, Calif., the company’s chief executive, Timothy D. Cook, penned a passionate letter warning of far-reaching implications beyond the case.

The response from other technology companies? A mix of carefully calibrated support and crickets.

Late on Wednesday, Sundar Pichai, the chief executive of Google, said on Twitter that law enforcement demands to hack customer devices and data “could be a troubling precedent.” Not long afterward, Reform Government Surveillance, a coalition formed by Apple, Google, Microsoft and Facebook, released a broad statement that did not mention the Apple case or Mr. Cook’s letter but said technology companies should not be required to put “back doors” — the equivalent of a tech entryway — into their products.

Asked about Apple’s opposition to the court order, representatives of Microsoft, Twitter and Facebook declined to comment. A spokesman for Amazon, which is not in the coalition, also declined to comment.

The range of reactions highlights the complicated set of factors influencing tech companies’ responses to government demands for customer data in the era after revelations by Edward J. Snowden, the former intelligence contractor, of widespread government surveillance. Some companies may be keeping their heads low to avoid becoming targets during the raucous presidential campaign, while others may fear that being too vocal will jeopardize government sales and relationships with law enforcement, privacy experts said.

“The issue is of monumental importance, not only to the government and Apple but to the other technology giants as well,” said Tom Rubin, a former attorney for Microsoft and the United States Department of Justice, who is now a law lecturer at Harvard University. “Those companies are undoubtedly following the case intently, praying that it creates a good precedent and breathing a sigh of relief that it’s not them in the spotlight.”