Compared with other countries, the United States has a strong guarantee of speech rights even for corporations, and at least one court has ruled that computer code is a form of speech, although that ruling was later voided.
Apple could argue that being required to create and provide specific computer code amounts to unlawful compelled speech, said Riana Pfefferkorn, a cryptography fellow at Stanford University's Center for Internet and Society.
The order against Apple is novel because it compels the company to create a new forensic tool to use, not just turn over information in Apple's possession, Pfefferkorn said. "I think there is a significant First Amendment concern," she said.
A spokesman for the U.S. Attorney's Office in Los Angeles declined to comment on the possible free-speech questions on Thursday.
A speech-rights argument from Apple, though, could be met with skepticism by the courts because computer code has become ubiquitous and underpins much of the U.S. economy.
"That is an argument of enormous breadth," said Stuart Benjamin, a Duke University law professor who writes about the First Amendment. He said Apple would need to show that the computer code conveyed a "substantive message."
In a case brought by a mathematician against U.S. export controls, a three-judge panel of the 9th U.S. Circuit Court of Appeals, which covers California, found in 1999 that the source code behind encryption software is protected speech. The opinion was later withdrawn so the full court could rehear the case, but that rehearing was canceled and the appeal declared moot after the government revised its export controls.