Unless Congress acts, Americans will soon benefit from one of the Patriot Act's most important safeguards against abuse: Language in Section 215 of the law is scheduled to expire in June, depriving the FBI and NSA of a provision they've used to justify monitoring the phone calls of tens of millions of innocents (though a primary author of the law insists that it grants no such authority). If you've used a landline to call an abortion clinic, a gun store, a suicide hotline, a therapist, an oncologist, a phone sex operator, an investigative journalist, or a union organizer, odds are the government has logged a record of the call. If your Congressional representative has a spouse or child who has made an embarrassing phone call, the executive branch may well possess the ability to document it, though government apologists insist that they'd never do so and are strangely confident that future governments composed of unknown people won't either.

Americans know about this intrusive spying on innocents thanks to Edward Snowden, the Booz Allen Hamilton contractor whose leaks revealed what national security officials hid even when doing so required lying in sworn testimony. In the aftermath of Snowden's leaks, the NSA argued that the phone dragnet is an important counterterrorism tool subject to careful safeguards against abuse. Keith Alexander went so far as to insist that it helped foil multiple terror plots.

But after an independent review of the program, the Privacy and Civil Liberties Oversight Board, a bipartisan agency within the executive branch, concluded that "the operation of the NSA’s bulk telephone records program bears almost no resemblance" to the statutory language that supposedly justifies it. In addition to declaring the program illegal and Constitutionally suspect, their report noted that "the Section 215 program has shown minimal value in safeguarding the nation from terrorism. Based on the information provided to the Board, including classified briefings and documentation, we have not identified a single instance involving a threat to the United States in which the program made a concrete difference in the outcome of a counterterrorism investigation."

Put simply, the phone dragnet risks the possibility of significant abuses yet offers scant benefits. It's the sort of excess in the War on Terror that ought to be easy to end.

In fact, even some within the spy community urged that course, according to AP. "The National Security Agency considered abandoning its secret program to collect and store American calling records in the months before leaker Edward Snowden revealed the practice, current and former intelligence officials say, because some officials believed the costs outweighed the meager counterterrorism benefits," the news organization reported. "After the leak and the collective surprise around the world, NSA leaders strongly defended the phone records program to Congress and the public, but without disclosing the internal debate."

Whether Congress will attempt to renew the program remains unclear.

Law professor Orin Kerr argues that one of several lawsuits against the program could influence legislators if a court decision is handed down prior to the Section 215 sunset. After listening to oral arguments in the Second Circuit, for example, he speculated that the court may conclude that Section 215 doesn't actually authorize the phone dragnet (a position that many civil libertarians have long insisted upon).

Harley Geiger argues that even if Section 215 sunsets, the Obama Administration could continue the surveillance:

First: The Sec. 215 sunset provision permits surveillance programs for investigations that began before the sunset to remain in place. The government could argue this allows it to continue with existing bulk collection programs to further broad investigations into terrorist groups commenced prior to the sunset – and which could endure indefinitely, regardless of the sunset, since the FBI puts no time limit on full investigations.

Second: Even if Sec. 215 were to sunset, the government could use the FISA pen/trap statute – which has a “relevant to an investigation” standard similar to that in Sec. 215 – for domestic bulk collection. The government cited the FISA pen/trap statute as authority for collection of Americans’ email metadata (who emailed who, when) until 2011, before shutting down the program due to lack of effectiveness and resource constraints. The pen/trap statute does not cover as many types of records as Sec. 215, but pen/trap would include phone and Internet communications. Unlike Sec. 215, the FISA pen/trap statute has no sunset.

Marcy Wheeler is suspicious that the Obama Administration is planning to continue the dragnet under different authorities. But Ned Price, a National Security Council spokesman, told Reuters that if Section 215 is not reauthorized the phone dragnet will end, depriving America of "a critical national-security tool that is used in a variety of additional contexts that do not involve the collection of bulk data."

If Congress does attempt to reauthorize Section 215 in its present form, it is likely to divide GOP presidential candidates and benefit the anti-surveillance faction: According to a recent Pew survey of Republicans who have heard of mass surveillance programs, 70 percent say they're losing faith that they serve the public interest. So Rand Paul and Ted Cruz would doubtless relish getting a likely primary opponent like Marco Rubio on record trying to extend the mass spying. Whether you're a Republican or a Democrat—and whether you're for or against reauthorization—the time to contact your Congressional representative is now. This is just the sort of occasion when letters, emails and phone calls could make a difference.