In one of the most prominent legal challenges to government intelligence gathering since the Edward Snowden disclosures, the American Civil Liberties Union (ACLU) has filed a lawsuit against four top Obama Administration officials. The case, known as ACLU v. Clapper, asks a federal judge to declare the entire metadata sharing program unlawful, halt it, and purge all related records.

On Thursday, Rep. James Sensenbrenner (R-WI), with representation from the Electronic Frontier Foundation (EFF), filed an amicus brief with the court. He noted that the vast data handover is not at all what Congress intended to happen. And Sensenbrenner should know, too, because he authored the Patriot Act in October 2001 and supported its subsequent reauthorizations. In particular, Section 215 of that law, which expanded government surveillance power of business records, is what the government argues gives it the authority to collect metadata in bulk.

Sensenbrenner writes:

The vast majority of the records collected will have no relation to the investigation of terrorism at all. This collection of millions of unrelated records is built-in to the mass call collection program. Defendants’ theory of “relevance” is simply beyond any reasonable understanding of the word. And it certainly is not what amicus intended the word to mean. … Defendants do not explain why Congress would have enacted such meaningless provisions. The bulk data collection program is unbounded in its scope. The NSA is gathering on a daily basis the details of every call that every American makes, as well as every call made by foreigners to or from the United States. How can every call that every American makes or receives be relevant to a specific investigation?

In previous court filings, the government has relied on a well-established (but increasingly challenged) part of American case-law known as the “third-party doctrine.” This notion says that when a person has voluntarily disclosed information to a third party—in this case, the telco—the customer no longer has a reasonable expectation of privacy over numbers dialed or call duration. Therefore, this doctrine argues, such metadata can be accessed by law enforcement with essentially no problem.

Also on Thursday other amici joined the ACLU v. Clapper case, including Michael Lynch, a professor of philosophy at the University of Connecticut, the Reporters Committee for the Freedom of the Press, and the National Rifle Association (NRA). The NRA even argued that the creation of a vast phone records database constituted a de facto gun owners’ list.

"Under the government’s reading of Section 215, the government could simply demand the periodic submission of all firearms dealers’ transaction records, then centralize them in a database indexed by the buyers’ names for later searching," the NRA writes in its filing.