The ACLU and the ACLU of Northern California filed a friend-of-the-court brief yesterday on behalf of three of Congress’s most staunch defenders of Americans’ privacy rights — Senators Ron Wyden (D-Ore.), Mark Udall (D-Colo.), and Martin Heinrich (D-N.M.) — in a challenge to the NSA’s mass collection of the phone records of virtually all Americans.

The brief was filed in the Northern District of California, in First Unitarian Church v. National Security Agency. Our friends at the Electronic Frontier Foundation filed the suit on behalf of 22 organizations ranging from church groups to gun-ownership advocates who claim that the government’s bulk collection of phone records violates their constitutional rights of free speech, association, and privacy.

The ACLU has leveled its own challenge to the program, which the government claims is authorized by Section 215 of the Patriot Act. A federal court in New York will hear oral argument on Friday in our lawsuit, ACLU v. Clapper, on the ACLU’s motion for a preliminary injunction and the government’s motion to dismiss the case.

For years, Senators Wyden and Udall have sounded the alarm with respect to the breadth of the government’s secret interpretation of Section 215. Now that the mass call-tracking program has been publicly disclosed, the government has defended the program by making aggressive claims about the unique value the program plays in the government’s counterterrorism efforts.

But Senators Wyden, Udall, and Heinrich — all three of whom sit on the Senate Select Committee on Intelligence — say they have seen no evidence backing up the government’s claims. The amicus brief the ACLU filed today on their behalf makes one central point in support of the First Unitarian Church plaintiffs’ motion for partial summary judgment:

As members of the committee charged with overseeing the National Security Agency’s surveillance, Amici have reviewed this surveillance extensively and have seen no evidence that the bulk collection of Americans’ phone records has provided any intelligence of value that could not have been gathered through less intrusive means. The government has at its disposal a number of authorities that allow it to obtain the call records of suspected terrorists and those in contact with suspected terrorists.

When government surveillance infringes on Americans’ First Amendment rights, it must demonstrate that it is using the least intrusive means to accomplish its objectives. Similarly, when courts review whether a surveillance scheme is reasonable under the Fourth Amendment, they consider whether it could be designed in a more targeted way. The senators’ amicus brief demonstrates that the government’s mass call-tracking program goes far beyond what is necessary to track the associations of suspected terrorists and needlessly sweeps in many sensitive details of the lives of ordinary Americans.

The amicus filing adds another chapter to the Senators’ efforts to defend Americans’ privacy. Senator Wyden explained that “it was important for us to file an amicus brief in this case to ensure that the court is aware of our understanding of the facts as it considers the important constitutional questions raised by this case.” Senator Udall added that because “the dragnet collection of millions of innocent Americans’ private phone records is a clear threat to our constitutional rights,” it was time for the court to “exercise their power and call out the government’s position.” And Senator Heinrich described the brief as an effort to “keep the government honest about what it tells others, including our courts, about this program.”

Senators Wyden, Udall, and Heinrich are the latest members of Congress to file briefs in support of litigation concerning Section 215 — and that list is growing. In June, a group of members of the House of Representatives led by Justin Amash (R­-Mich.) filed an amicus brief in support of the ACLU’s motion for public access to the opinions of the secretive Foreign Intelligence Surveillance Court that interpret Section 215. And in September, Jim Sensenbrenner (R-Wis.), one of the original authors of the Patriot Act, filed an amicus brief in support of the ACLU in ACLU v. Clapper, arguing that Congress never intended to grant the government the power to collect records in bulk under Section 215.