In a 50-page ruling that read like a Supreme Court brief, he rejected in no uncertain terms the Department of Justice’s aggressive use of the broad powers of the 1789 All Writs Act to force Apple to do its bidding in San Bernardino.

“Ultimately, the question to be answered in this matter and in others like it across the country,” he wrote, “is not whether the government should be able to force Apple to help it unlock a specific device; it is instead whether the All Writs Act resolves that issue and many others like it yet to come.”

Using the word “tyranny” once and “absurd” nine times, Judge Orenstein accused the DOJ of trying to use the authority of the All Writs Act to get through the courts what it couldn’t get from Congress.

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“Its preferred reading of the law,” he wrote, “would transform the [All Writs Act] from a limited gap-filing statute that ensures the smooth functioning of the judiciary itself into a mechanism for upending the separation of powers.”

It’s one thing for Tim Cook and his supporters in Silicon Valley to accuse the government of over-reaching. It’s quite another when the accusation comes from a federal judge.

The fierceness with which Judge Orenstein came down on Apple’s side should strengthen the company’s hand on a day when its general counsel is scheduled to testify about the San Bernardino standoff before a congressional subcommittee. Among the judge’s best lines:

• The implications of the government’s position are so far-reaching—both in terms of what it would allow today and what it implies about Congressional intent in 1789—as to produce impermissibly absurd results.
• In its most recent use of the [All Writs Act] it goes so far as to contend that a court—without any legislative authority other than the AWA—can require Apple to create a brand new product that impairs the utility of the products it is in the business of selling.”
• “It is also clear that the government has made the considered decision that it is better off securing such crypto-legislative authority from the courts [than] taking the chance that open legislative debate might produce a result less to its liking.”
• “It would be absurd to posit that the authority the government sought was anything other than obnoxious to the law.”

For more on Apple vs. FBI, watch this video: [fortune-brightcove videoid=4773238767001]

“The government’s motion,” he concludes, “is denied. “