Here’s a look at the FISA Court and FISA warrants.

What is the FISA Court?

A warrant to wiretap someone suspected of spying with or for a foreign government is issued by the Foreign Intelligence Surveillance Court -- or FISA Court. The court is actually a tribunal whose actions are carried out in secret. The tribunal has the authority to grant warrants for electronic surveillance. The court has 11 members, all federal judges. The judges serve seven-year terms. The chief justice of the U.S. Supreme court selects the judges.

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When was this court established?

The Foreign Intelligence Surveillance Act of 1978 created the court and set up the rules for wiretapping of suspected spies.

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What is its mission?

The court was set up to either approve or deny warrants requested by the United States government for surveillance of foreign spies inside of the United States. That warrant requests and the intelligence gathering is generally done by federal law enforcement agencies or U.S. intelligence agencies. The authorization allows for wiretapping a "foreign power or an agent of a foreign power" (which could include American citizens) suspected to be engaged in espionage or terrorism. Methods used in an investigation include electronic surveillance, physical searches and other actions. Generally, the attorney general signs the warrant requests.

How does it work?

When an agency requests a warrant from the FISA Court, the request falls to one of the 11 judges who sit on the court. It is up to that judge to either deny or approve the request for a surveillance warrant. If the request is denied, there is an avenue for appeal of the ruling, but that has happened only a handful of times in the history of the court.

Is there any other way to get surveillance warrant?

An alternate way a warrant for surveillance can be obtained is if the U.S. attorney general declares an emergency and authorizes the employment of the surveillance. The attorney general must notify a judge on the FISA Court, and must, within seven days, apply for a warrant for the action.

What rules must they follow?

While the proceedings are secret, there are rules that have to be followed. The statute that created FISA Courts bars targeted electronic surveillance in the United States unless there is evidence that a foreign power or agent of a foreign power is involved. Also, there has to be evidence that the facility -- an email address or phone number, for instance -- is being used by the foreign power or agent. In addition, the government must show that the information to be collected is "relevant" to any investigation of foreign espionage or terrorism.

The warrants are generally issued for up to 12 months, and they authorize the government to collect “bulk information.” That means that while Americans on U.S. soil who are not agents of a foreign government are not targeted, information collected could include communication between U.S. citizens.

Can public see these warrants, they can see others?

The court’s dealings are secret, the hearings closed to the public. Records are made and kept, but those records are generally not made available to the public.

How many have been turned down?

As of 2013, the FISA court has denied only 12 warrants since its inception. It has granted more than 34,000 requests since its inception.