Today, prosecutors filed a new motion seeking to compel Apple to break security measures on an iPhone used in the San Bernardino attacks. "The government and the community need to know what is on the terrorist’s phone, and the government needs Apple’s assistance to find out," the filing argues. " Apple’s rhetoric is not only false, but also corrosive of the very institutions that are best able to safeguard our liberty and our rights."

Apple had previously argued that congress explicitly forbade the kind of compelled action proposed by the government's initial order, pointing to 1994's Communications Assistance to Law Enforcement Act as relevant precedent. But prosecutors pushed back against that logic in today's filing, arguing that congressional inaction did not preclude the order. The filing quotes a Supreme Court ruling in US v. Craft, which reads:

Failed legislative proposals are a particularly dangerous ground on which to rest an interpretation of a prior statute, reasoning that congressional inaction lacks persuasive significance because several equally tenable inferences may be drawn from such inaction, including the inference that the existing legislation already incorporated the offered change.

The government also questions Apple's assertion that the proposed firmware update would pose a threat to iPhone security more broadly, one that has been echoed by a number of security experts. "There is no reason to think that the code Apple writes in compliance with the Order will ever leave Apple’s possession. Nothing in the Order requires Apple to provide that code to the government or to explain to the government how it works," the filing argues. "Far from being a master key, the software simply disarms a booby trap affixed to one door."

The filing also pushes back against the idea that the information sought by the FBI could have been obtained through an iCloud backup, an idea put forward by many Apple defenders in the weeks since the initial order. The FBI has drawn criticism for resetting the iCloud password in the wake of the attack, but according to attached FBI testimony, Farook himself had reset the password three days after the final backup, potentially cutting off any subsequent backups. The FBI also testified that the phone was powered-down when recovered, which would have made it impossible to connect to a Wi-Fi signal without first entering the passcode.

In a response to the brief, Apple general counsel Bruce Sewell described the filing as hostile to an unprecedented degree. "I don't think I've ever seen a legal brief more intended to smear the other side," said Sewell in a call with reporters. "To do this in a brief just shows the desperation that the Department of Justice is now feeling."

6:20PM ET: Updated with Apple's response to the brief.