After passing a surveillance reform bill last year, Congress appears poised to turn to examine another controversial surveillance authority — Section 702 of FISA. Using Section 702, the government copies, searches, and retains vast quantities of Americans’ international communications, all without ever obtaining a warrant.

On Tuesday, the House Judiciary Committee held its first hearing, in what we hope is a series, on Section 702 this Congress. Unfortunately, because the hearing was closed to the public, we do not know what issues were raised. In the past, Congress has reauthorized Section 702 without key information. However, we hope that members of Congress made clear that they would not reauthorize Section 702 when it is set to expire in 2017 without, at a minimum, answering the following key questions:

1. How many Americans have had their private information collected?

The government’s Section 702 position is inherently contradictory: Officials insist that the surveillance does not violate Americans’ rights, yet claim they have no way of knowing how many Americans’ communications are even collected.

The demand for information about the number of Americans whose information is collected under Section 702 is not new. Sen. Wyden has repeatedly asked Director of National Intelligence James Clapper for this information. Indeed, the Privacy and Civil Liberties Oversight Board explicitly noted that it requested but was not able to get this information as part of its review of Section 702.

Despite these requests, the government has staunchly refused to provide an account of the number of Americans whose information is collected and searched under Section 702. The primary justifications for this refusal have been that calculating this information would not be possible and, ironically, would require the government to commit additional privacy intrusions (presumably because it would require review of communications that otherwise would not be searched).

These justifications simply don’t stand up to scrutiny. First, the government has yet to provide concrete, detailed information on the resources that would be needed to obtain this information. Second, in response to a Foreign Intelligence Surveillance Court inquiry regarding the number of wholly domestic communications collected under Section 702, the NSA conducted a sampling of thousands of communications to provide a rough estimate of this information. With appropriate privacy protections, the intelligence community could use a similar methodology to estimate the number of Americans whose information is collected.

2. What is the legal justification for using Section 702 to scan virtually all Americans’ international communications over the Internet?

Over the past three years, it has become clear that the government often performs legal acrobatics in order to justify surveillance that was never authorized by Congress in the first place. Such acrobatics appear to extend to the NSA’s “Upstream surveillance,” which it operates under Section 702.

Upstream surveillance involves the mass copying and searching of virtually all Internet communications flowing into and out of the United States. With the help of companies like Verizon and AT&T, the NSA conducts this surveillance by tapping directly into the Internet backbone inside the United States — the physical infrastructure that carries the communications of hundreds of millions of Americans and others around the world. After copying nearly all of this traffic, the NSA searches the metadata and content for key terms, called “selectors,” that are associated with its thousands of foreign targets. Communications that contain these selectors can be retained and analyzed by the NSA with few restrictions.

The ACLU and other groups have challenged the mass searches and seizures of Americans’ internet communications under Upstream surveillance as both a violation of the Fourth Amendment and a violation of the restrictions that Congress wrote into Section 702 itself. Thus, it is critical that Congress press the intelligence community to disclose its legal analysis — and that Congress take steps to ensure that Section 702 is not used to justify illegal and unconstitutional mass surveillance of Americans’ international communications.

3. How many “backdoor searches” does the FBI conduct each year?

Members of Congress are rightfully concerned that the government performs “backdoor searches” — where analysts and investigators search Section 702 databases for information using US person identifiers (for example, a US person’s name or phone number). These searches are not authorized by the text of Section 702, and are contrary to the intent of the law, which explicitly prohibits the use of Section 702 to target US persons.

The surveillance reform bill passed last year, the USA Freedom Act, requires some reporting on the number of backdoor searches — but conspicuously excludes the FBI from this requirement. This is despite the fact that the Privacy and Civil Liberties Oversight Board reported that the FBI conducts backdoor searches in virtually every national security investigation and many other criminal investigations.

The FBI is clearly capable of tracking its use of backdoor searches. Other federal agencies, such as the CIA, account for the number of backdoor searches they perform. Given this, members of Congress should aggressively push the FBI to provide an accurate account of the number of backdoor searches it performs. Such information is essential to assess the impact that warrantless surveillance under Section 702 has on Americans.

4. What are the rules for using Section 702 information in criminal prosecutions and investigations?

Are there cases where information obtained or derived from Section 702 is used to assist in low-level drug investigations, tax-fraud investigations, or other investigations that have nothing to do with national security? These basic questions about how Section 702 is used in domestic criminal investigations remain unanswered.

Section 702 was not intended to be used to investigate and prosecute domestic crimes — yet internal procedures appear to permit just that. Intelligence officials have publicly confirmed that internal regulations permit Section 702 information to be used as evidence at trial in a variety of domestic criminal contexts, including transnational drug crimes, certain forms of battery, and crimes involving damage to critical infrastructure. Moreover, it appears that government regulations permit the use of Section 702 information during the investigation stage of any crime.

Concerns over the widespread use of this information are compounded by the fact that the government has historically failed to fulfill its obligations to notify individuals when it intends to use information “obtained or derived” from Section 702 in legal proceedings against them. Although the Justice Department began notifying criminal defendants of the use of Section 702-derived information in October 2013, it has done so in only five cases, and there has not been a single notification in 22 months. In addition, other federal agencies, such as the Treasury Department, have never provided Section 702 notifications, despite their reliance on this information.

These practices are at odds with the intent of the law and represent an end run around the Fourth Amendment’s warrant requirement. Given this, it is critical that the intelligence community be required to disclose more information about the use of Section 702 information in criminal investigations and prosecutions.

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Many of these questions should have been answered before Section 702 was ever passed. Now, Congress should demand these answers as it considers how to reform Section 702 to protect the privacy rights of Americans and others.