Mike Snider, and Jon Swartz

USA TODAY

The American Civil Liberties Union on Wednesday kicked off what is expected to be a string of amicus briefs in federal court to support Apple in the tech company's fight against a court order to unlock an encrypted iPhone used by one of the San Bernardino shooters.

In an amicus brief to be filed Wednesday, the ACLU has called the case — in which the FBI wants Apple to help it gain access to the iPhone 5C used by Syed Rizwan Farook, who, along with his wife, is suspected of killing 14 and injuring 22 in the Dec. 2 terror assault — unlawful and unconstitutional.

"This case concerns an unprecedented law-enforcement effort to conscript an American technology company into creating software designed to weaken the security of its own devices — an effort that, if successful, would set precedent implicating the security and privacy of hundreds of millions of Americans," according to a statement from the ACLU.

Apple files appeal against iPhone order

Apple is fighting a Feb. 16 order from a federal magistrate in California that the company must help the FBI try to get into gunman Farook's iPhone by disabling a feature that would lock investigators out if they made 10 unsuccessful tries to determine the correct password. Apple CEO Tim Cook has called the request akin to creating a "backdoor" into the iPhone.

Late Tuesday, Apple filed an appeal against the iPhone order.

Apple files appeal against iPhone order

A slew of tech companies are expected to line up in support of Apple. Google, Facebook and Twitter are part of a coalition expected to file unsolicited amicus briefs on behalf of Apple. The deadline to file such documents is Thursday.

The Electronic Frontier Foundation and Amnesty International also say they'll support Apple.

Apple rival Samsung, which battled Apple for years in a patent-infringement lawsuit, said it has not decided whether to file an amicus brief in the Apple-FBI clash.

The ACLU argues in the brief that such a requirement would have far-reaching consequences that would undermine the public's right to privacy.

"If the government prevails, then this case will be the first of many requiring companies to degrade the security and to undermine the trust in their products so essential to privacy in the digital age," it writes. "For the many users who rely on digital devices to secure their information and communications, including members of vulnerable populations who rely on mobile devices to access the Internet, this burden would be severe."

Pro-privacy groups Access Now and Wickr Foundation filed a joint amicus brief asking a California judge to vacate her order in favor of the government. “A loss for Apple in this case is a loss for human rights around the world,” said Amie Stepanovich, U.S. policy manager at Access Now.

In a similar case in Brooklyn, where a judge ruled in favor of Apple on Monday, the judge declined to accept amicus briefs from the ACLU, New York Civil Liberties Union and representatives of the Stanford Center for Internet and Society that backed Apple.

Contributing: Kevin McCoy in New York.

Follow @MikeSnider and @jswartz on Twitter.