The fight over Apple’s refusal to help the FBI break into an iPhone used by a terrorist in California is destined for Washington. The only question is whether it will be Congress or the Supreme Court that breaks the impasse.

Apple argues the Justice Department is overstepping its authority by forcing the company to help disable the encryption on an iPhone used by one of the two shooters who killed 14 people at a holiday party in San Bernardino on Dec. 2. The company’s argument that lawmakers failed to give prosecutors the power they are seeking reveals a gambit that the Supreme Court will side with it on privacy and block an attempt to make it a “hacking” department for the government.

Apple said Thursday, in its first response in court to a judge’s order to help the government, that relying on a law that predates smartphones by more than two centuries is unprecedented and threatens the civil liberties of hundreds of millions of mobile phone users.

That law, the All Writs Act of 1789, has been used by prosecutors to obtain court orders to enforce search warrants where there’s a legal vacuum. Apple contends Congress has had the chance to expand the power of law enforcement to access encrypted data on smartphones and has not.

A Receptive Court

The Supreme Court ruled unanimously in 2014 that police must get a warrant before searching a mobile phone. Chief Justice John Roberts, in a ruling that indicates Apple may have a receptive audience for its privacy arguments, said cell phones weren’t merely a technological convenience. “With all they contain and all they may reveal, they hold for many Americans the privacies of life,” Roberts said.

Whether the All Writs Act gives the U.S. the authority – once it obtains a warrant to compel the company to write new software to unlock a mobile phone – goes beyond the scope of that 2014 ruling.

“At a minimum, what should happen is Congress should legislate in this area” of national security, with the courts then weighing the constitutionality of the legislation, said David Rudenstine, a professor at Benjamin N. Cardozo School of Law. “We shouldn’t backdoor it and allow the government to get its hands on this kind of power by relying on an 18th-century statute.”

A former aide to the Obama administration’s national security staff said that by trying to use Congress’ inaction as an excuse to force the court to rule, Apple may be playing into the hands of Federal Bureau of Investigation Director James Comey.

“The FBI is playing chess. If they win, they have a precedent for demanding assistance from Apple,” said Timothy Edgar, a senior fellow at Brown University’s Watson Institute for International and Public Affairs. “If they lose, they have a perfect argument to go back to Congress.”

Apple may not like what it gets from lawmakers, Edgar said.

“I just have a hard time imagining government legislation that would be to the liking of the technology industry,” Edgar said.

The dispute between Apple and the FBI is part of a larger debate within Congress, the administration and the technology industry about whether law enforcement and intelligence agencies should be able to access encrypted communications. The issue has sharply divided lawmakers, and thwarted past efforts to reach compromise.