Apple filed court papers on Thursday urging a judge to overturn her order requiring it to unlock an iPhone used by one of the shooters in last December's San Bernardino attacks.
Forcing it to help unlock the phone would set a dangerous precedent that would undermine security for all its customers and open the door to more invasive government requests in future, Apple argued.
"If Apple can be forced to write code in this case to bypass security features and create new accessibility, what is to stop the government from demanding that Apple write code to turn on the microphone in aid of government surveillance, activate the video camera, surreptitiously record conversations, or turn on location services to track the phone’s user? Nothing," the company's lawyers wrote.
The government has argued that the software it's asking Apple to create will be used on only this one phone. That's is not true, the company argued.
"The government says: 'Just this once' and 'Just this phone,'" the company's lawyers argued. "But the government knows those statements are not true; indeed the government has filed multiple other applications for similar orders, some of which are pending in other courts."
"Once the floodgates open, they cannot be closed, and the device security that Apple has worked so tirelessly to achieve will be unwound without so much as a congressional vote."
Prosecutors argue the data on the iPhone is necessary for the ongoing terrorism investigation. The information could help investigators find collaborators of the mass shooters, prosecutors argued.
Apple said it strongly supports the efforts of law enforcement, but that the government's request is unsupported by the law and would "violate the Constitution."
If the judge declines to overturn her order, legal experts have said the case could go all the way to the U.S. Supreme Court.