The law that the Obama administration cites to allow bulk telephone metadata collection expires on June 1, and the FBI has already begun lobbying to keep Section 215 of the Patriot Act from expiring. Bad guys "going dark" using encryption, the FBI says, is one of the reasons why the government needs to collect the metadata of every phone call made to and from the United States.

Robert Anderson, the FBI’s chief of the Criminal, Cyber, Response, and Services Branch, told reporters during a roundtable discussion Tuesday that the Patriot Act is necessary because encrypted communications are becoming more commonplace in the wake of the Edward Snowden disclosures.

"In the last two to three years, that whole ‘going dark’ thing went from a crawl to a flat-out sprint because the technology is changing so rapidly," Anderson said.

Joseph Demarest, assistant director of the FBI's Cyber Division, told reporters that if Section 215 expires, "Obviously it’s going to impact what we do as an organization and certainly on cyber."

The comments, especially as they relate to encryption, are part of a growing chorus of calls—from as high as President Barack Obama—that the government needs Silicon Valley's assistance for backdoors into encrypted tech products like the iPhone.

Silicon Valley has (at least publicly) shunned the administration's attempts to get backdoors into their products. And while no legislation at the moment requires them to comply, the nation's spy apparatus and others are turning their attention toward not losing the bulk telephone metadata spying program that spun heads when The Guardian—armed with classified documents from Snowden—exposed it in 2013. As it turns out, the secret Foreign Intelligence Surveillance Act court that was authorizing the program was doing so under the authority of Section 215 of the Patriot Act.

While many leading lawmakers are behind renewing the program, there are plenty of reasons why it should expire come June. According to the EFF:

...the President’s Review Board said 'the information contributed to terrorist investigations by the use of section 215 telephony meta-data was not essential (PDF) to preventing attacks.' And the Privacy and Civil Liberties Oversight Board could not identify one time when bulk collection under Section 215 of the PATRIOT Act 'made a concrete difference in the outcome of a counterterrorism investigation.' Similarly, an in-depth analysis of 225 cases of people charged with terrorism found that 'the contribution of NSA’s bulk surveillance programs to these cases was minimal.'

One federal judge has upheld the program while another has declared it unconstitutional. A Supreme Court showdown over the snooping isn't likely to happen any time soon.

There's plenty of rhetoric on all sides of the issue, too. Sen. Marco Rubio (R-FL) said Section 215 should never expire. House Speaker John Boehner (R-Ohio) and Majority Leader Mitch McConnell (R-KY) are big fans of Section 215.

Sens. Ron Wyden (D-OR) and Martin Heinrich (D-NM) said that "none of the claims appear to hold up to scrutiny" that the bulk metadata collection program prevents terrorism.

When Congress publicly re-authorized Section 215 three years ago, the public didn't know that lawmakers were secretly approving the bulk telephone metadata program. And some lawmakers who had voted for re-authorization claimed that they didn't even know about the bulk collection program.

At least this time, when it comes up for a vote in the coming months, lawmakers can't claim that they didn't know they were voting to allow the government to scoop up data that includes phone numbers of parties involved in calls, calling card numbers, the time and duration of the calls, and the international mobile subscriber identity number for mobile callers.

The database is said to have more than 1 trillion records.