The United States Foreign Intelligence Surveillance Court (FISC; also called the FISA Court) is a U.S. federal court established under the Foreign Intelligence Surveillance Act of 1978 (FISA) to oversee requests for surveillance warrants against foreign spies inside the United States by federal law enforcement and intelligence agencies.

FISA was created by the U.S. Congress based on the recommendations of the Senate's Church Committee, which was convened in 1975 to investigate illicit activities and civil rights abuses by the federal intelligence community. Pursuant to the law, the FISC reviews requests to conduct physical and electronic surveillance within the U.S. concerning "foreign intelligence information" between "foreign powers" and "agents of foreign powers" suspected of espionage or terrorism; such requests are made most often by the National Security Agency (NSA) and the Federal Bureau of Investigation (FBI).

From its opening in 1978 until 2009, the court was housed on the sixth floor of the Robert F. Kennedy Department of Justice Building. Since 2009, it has been relocated to the E. Barrett Prettyman United States Courthouse in Washington, D.C. "For about 30 years, the court was located on the sixth floor of the Justice Department's headquarters, down the hall from the officials who would argue in front of it. (The court moved to the District's federal courthouse in 2009.)"

Warrants Each application for one of these surveillance warrants (called a FISA warrant) is made before an individual judge of the court. The court may allow third parties to submit briefs as amici curiae. When the United States Attorney General determines that an emergency exists, they may authorize the employment of electronic surveillance before obtaining the necessary authorization from the FISC, if the Attorney General or their designee notifies a judge of the court at the time of authorization and applies for a warrant as soon as practicable but not more than seven days after authorization of such surveillance, as required by . If an application is denied by one judge of the court, the federal government is not allowed to make the same application to a different judge of the court but may appeal to the United States Foreign Intelligence Surveillance Court of Review.

Such appeals are rare: the first appeal from the FISC to the Court of Review was made in 2002 (In re Sealed Case No. 02-001), 24 years after the founding of the court. FISA warrant requests are rarely denied. During the 25 years from 1979 to 2004, 18,742 warrants were granted, while only four were rejected. Fewer than 200 requests had to be modified before being accepted, almost all of them in 2003 and 2004. The four rejected requests were all from 2003, and all four were partially granted after being submitted for reconsideration by the government. Of the requests that had to be modified, few were before the year 2000. During the next eight years, from 2004 to 2012, there were over 15,100 additional warrants granted, and another seven being rejected. Over the entire 33-year period, the FISA court granted 33,942 warrants, with only 12 denials – a rejection rate of 0.03 percent of the total requests. This does not include the number of warrants that were modified by the FISA court.

+ FISA warrant requests for electronic surveillance Year # Requestssubmitted # Requestsapproved # Requestsmodified # Requestsdenied 1979 199 207 0 0 1980 319 322 1 0 1981 431 433 0 0 1982 473 475 0 0 1983 549 549 0 0 1984 635 635 0 0 1985 587 587 0 0 1986 573 573 0 0 1987 512 512 0 0 1988 534 534 0 0 1989 546 546 0 0 1990 595 595 0 0 1991 593 593 0 0 1992 484 484 0 0 1993 509 509 0 0 1994 576 576 0 0 1995 697 697 0 0 1996 839 839 0 0 1997 749 748 0 0 1998 796 796 0 0 1999 886 880 0 0 2000 1,005 1,012 1 0 2001 932 934 4 0 2002 1,228 1,228  2  0 0 2003 1,727 1,724 79 4 2004 1,758 1,754 94 0 2005 2,074 2,072 61 0 2006 2,181 2,176 73 1 2007 2,371 2,370 86 4 2008 2,082 2,083 2 1 2009 1,329 1,320 14 2 2010 1,511 1,506 14 0 2011 1,676 1,674 30 0 2012 1,789 1,788 40 0 2013 1,588 1,588 34 0 2014 1,379 1,379 19 0 2015 1,457 1,456 80 5 2016 1,485 1,451 310 34 2017 1,372 948 353 71 2018 1,142 830 245 67 2019 863 586 224 53 2020 489 334 121 34 2021 391 271 97 23 2022 358 249 87 23 2023 363 270 78 14 Totals 41,222 40,668 1,252 85 Notes:

On May 17, 2002, the court rebuffed Attorney General John Ashcroft, releasing an opinion that alleged that the FBI and Justice Department officials had "supplied erroneous information to the court" in more than 75 applications for search warrants and wiretaps, including one signed by FBI director Louis J. Freeh. Whether this rejection was related to the court starting to require modification of significantly more requests in 2003 is unknown. On December 16, 2005, The New York Times reported that the Bush administration had been conducting surveillance against U.S. citizens since 2002 without specific approval from the FISA court for each case.Risen, James; Lichtblau, Eric (December 16, 2005). "Bush Lets U.S. Spy on Callers Without Courts". The New York Times.

On December 20, 2005, Judge James Robertson resigned his position on the court, apparently in protest of the secret surveillance,Leonnig, Carol D.; Linzer, Dafna (December 21, 2005). The Washington Post (via Information Clearing House). Retrieved July 11, 2013. and later, in the wake of the Snowden leaks of 2013, criticized the court-sanctioned expansion of the scope of government surveillance and its being allowed to craft a secret body of law. The government's apparent circumvention of the court started prior to the increase in court-ordered modifications to warrant requests. In 2011, the Obama administration secretly won permission from the Court to reverse restrictions on the National Security Agency's use of intercepted phone calls and e-mails, permitting the agency to search deliberately for Americans' communications in its databases. The searches take place under a surveillance program Congress authorized in 2008, under section 702 of FISA (section 1881a of Title 50 of the United States Code).

Under section 702, the target must be a foreigner "reasonably believed" to be outside the United States, and the court must approve the targeting procedures in an order good for one year. But a warrant for each target would thus no longer be required. That means that communications with Americans could be picked up without a court first determining that there is probable cause that the people they were talking to were terrorists, spies or "foreign powers". The FISC also extended the length of time that the NSA is allowed to retain intercepted U.S. communications from five years to six years with an extension possible for foreign intelligence or counterintelligence purposes. Both measures were taken without public debate or any specific authority from Congress.

Secrecy Because of the sensitive nature of its business, the court is a "secret court" meaning its hearings are closed to the public. While records of the proceedings are kept, they also are unavailable to the public, although copies of some records with classified information redacted have been made public. Due to the classified nature of its proceedings, usually only attorneys licensed to practice in front of the US government are permitted to appear before the court. Because of the nature of the matters heard before it, court hearings may need to take place at any time of day or night, weekdays or weekends; thus, at least one judge must be "on call", at all times, to hear evidence and decide whether or not to issue a warrant. A heavily redacted version of a 2008 appeal by Yahoo! of an order issued with respect to NSA's PRISM program had been published for the edification of other potential appellants. The identity of the appellant was declassified in June 2013.

Criticism There has been growing criticism of the court since the September 11, 2001, attacks. This is partly because the court sits ex parte – in other words, in the absence of anyone but the judge and the government present at the hearings. This, combined with the minimal number of requests that are rejected by the court has led experts to characterize it as a rubber stamp (former National Security Agency analyst Russ Tice called it a "kangaroo court with a rubber stamp").

The accusation of being a "rubber stamp" was rejected by FISA Court president Reggie B. Walton who wrote in a letter to Senator Patrick J. Leahy: "The annual statistics provided to Congress by the Attorney General ... – frequently cited to in press reports as a suggestion that the Court's approval rate of application is over 99% – reflect only the number of final applications submitted to and acted on by the Court. These statistics do not reflect the fact that many applications are altered to prior or final submission or even withheld from final submission entirely, often after an indication that a judge would not approve them." He added: "There is a rigorous review process of applications submitted by the executive branch, spearheaded initially by five judicial branch lawyers who are national security experts and then by the judges, to ensure that the court's authorizations comport with what the applicable statutes authorize."

In a following letter Walton stated that the government had revamped 24.4% of its requests in the face of court questions and demands in time from July 1, 2013, to September 30, 2013. This figure became available after Walton decided in the summer of 2013 that the FISC would begin keeping its own tally of how Justice Department warrant applications for electronic surveillance fared – and would track for the first time when the government withdrew or resubmitted those applications with changes. Some requests are modified by the court but ultimately granted, while the percentage of denied requests is statistically negligible (11 denied requests out of around 34,000 granted in 35 years – equivalent to 0.03%).

The accusation that the FISC is a "rubber stamp" court was also rejected by Robert S. Litt (General Counsel of Office of the Director of National Intelligence): "When [the Government] prepares an application for [a section 215 order, it] first submit[s] to the [FISC] what's called a "read copy", which the court staff will review and comment on. [A]nd they will almost invariably come back with questions, concerns, problems that they see. And there is an iterative process back and forth between the Government and the [FISC] to take care of those concerns so that at the end of the day, we're confident that we're presenting something that the [FISC] will approve. That is hardly a rubber stamp. It's rather extensive and serious judicial oversight of this process."

A 2003 Senate Judiciary Committee Interim Report on FBI Oversight in the 107th Congress by the Senate Judiciary Committee: FISA Implementation Failures cited the "unnecessary secrecy" of the court among its "most important conclusions":

Allegations of bias In a July 2013 interview, Senator and privacy advocate Ron Wyden described the FISC warrant process as "the most one-sided legal process in the United States". "I don't know of any other legal system or court that really doesn't highlight anything except one point of view", he said. Later in the interview he said Congress should seek to "diversify some of the thinking on the court".