The Justice Department wants Apple to write special software to help it break into the iPhone used by one the San Bernardino terrorists.

In its filing opposing a federal judge's order to help the government, Apple says it would be a violation of its First Amendment rights to free speech.

It's pretty well established that speech comes in many forms, says Eric Goldman, a professor at Santa Clara University School of Law. "We can talk, we can write words, we can draw paintings, we can take photographs ..."

Goldman says back in the 1990s, courts began to confront the question of whether software code is a form of speech. Goldman says the answer to that question came in a case called Bernstein v. US Department of Justice.

Daniel Bernstein was a student at the University of California, Berkeley, who created an encryption software called "Snuffle." Bernstein wanted to put it on the Internet, and the government tried to stop him using a law meant to stop the export of firearms and munitions.

Goldman says the student argued that his code was a form of speech.

"It clearly had expressive intent about what message the software author was trying to send to the world," Goldman says. "It was trying to say, 'I believe that privacy is important, and I'm going to use this software in order to express that.' "

The 9th U.S. Circuit Court of Appeals agreed, and software has been treated as a form of speech ever since.

Based on that, Apple is arguing that the First Amendment also prevents the government from telling it what to say — in this case, that it's OK to break through the security on its phones.

Andrew Crocker, an attorney with the Electronic Frontier Foundation, or EFF — a digital civil rights group — says the government can't make you say what you don't believe. He looks to a Supreme Court case from New Hampshire, Wooley v. Maynard.

"New Hampshire has a license plate that says 'Live Free or Die,' and someone objected to that on religious grounds," says Crocker. "And the court said, 'No, in fact you don't have to have that on your license plate.' "

But it's not that the government can't make you say anything you don't want to, says Professor Goldman: "There are plenty of circumstances where the government mandates people to speak — for example, you have to put the nutrition label on your can of food if you want to sell that food into the economy."

And just as there are safety issues involved in the sale of food, the government says there are safety issues in its case against Apple. It's possible there is something on the iPhone that tells of another pending plot against U.S. citizens.

EFF attorney Andrew Crocker says Congress could make rules that force Apple to cooperate.

"If you had a law that required them to do this in the first place, we might argue about whether that law is logical, or a good idea, or in fact is constitutional for other reasons" says Crocker. "But it would at least establish a baseline that Apple had to comply with. And that's not the case here — they were totally free to design their software the way they did."

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