Apple's court battle against the FBI isn't so cut and dry.
To force Apple to help the FBI unlock a San Bernardino shooter's iPhone, a federal magistrate-judge invoked the All Writs Act, which allows courts to make a company turn over a customer's data to law enforcement.
The legal argument Apple is expected to use can be summed up like this: Code is protected speech, so the government can't compel Apple to write a new version of iOS any more than it can force an author to write a story.
Apple (AAPL) has stated that the court's interpretation of the All Writs Act is overly expansive. Complying would endanger potentially millions of Apple customers by creating a back door that anyone could exploit, the company says.
There is some precedent that code is protected speech. In Bernstein vs. U.S. Department of Justice, the U.S. Court of Appeals for the Ninth Circuit ruled that the code in a developer's software was protected by the First Amendment.
Related: Tim Cook says unlocking terrorist's iPhone is 'bad for America'
"Apple's case raises some fairly obvious First Amendment issues," said Robert Corn-Revere, an attorney at DavisWrightTremaine who represented Dan Bernstein in his landmark case. "It's not a big leap to say the language for computers that changes instructions into actions is part of a communicative process."
But Corn-Revere also cautioned that Bernstein, which was never taken up by the U.S. Supreme Court, is the only case that has decided the issue.
An Apple spokesman said that the company is not discussing its legal strategy ahead of its response to a court order. That response is due on Friday.
Proving that code is protected speech isn't the biggest obstacle Apple faces. Core to Apple's argument against writing a new version of its operating system is that, by complying, it will make its customers less secure. But Apple would have to overcome years of precedent in the way that companies work with law enforcement.
"I'm sympathetic, but I can't think of any authority that says that you can evade your obligations to comply with the police because you don't trust they'll keep the information secure enough," said Lawrence Lessig, a Harvard Law professor and constitutional law scholar.
Lessig noted that the security issue makes Apple's case unique.
Related: Apple's next goal: an unbreakable iPhone
"If a bank has vault and the police have a search warrant, then there's no doubt that the bank has to open the vault," Lessig said. "But when bank opens vault, there's no concern that it's making every other vault unsafe."
The problem with the case, Lessig said, is that Apple is going to have to do a lot of work to convince the court that there's a new issue here. It has to prove that there's something different about its case.
"The Fourth Amendment says if you have a warrant, you have to open the safe," Lessig said. "That's a compelling argument. It sounds like fingers on a blackboard to people in the technology industry, but it's going to be hard to convince at least five justices on the Supreme Court otherwise."
