The Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism Act, more commonly known as the Patriot Act, was passed by Congress in October 2001 to give law enforcement increased powers in the fight against terrorism.
Running 342 pages, the law contains more than 150 sections, most of which are amendments to existing statutes.
The Patriot Act was first presented to Congress five days after the terror attacks of Sept. 11, 2001, and passed 45 days later. Written into the law were so-called "sunset" provisions, which set about 10 percent of the sections to expire on Dec. 31, 2005, unless Congress votes to keep them in effect.
The law was passed by overwhelming majorities in both houses of Congress -- by a 98-1 margin in the Senate and 356-66 in the House -- but since then a growing number of legislators have become critical of it. Most of those expressing concern have been Democrats.
Concerns from the public likewise have grown. At first the critics were mostly immigrants' rights groups and civil liberties advocates, but a number of conservative organizations and gun rights advocates have joined the call to re-examine the Patriot Act.
Across the country, seven states -- Alaska, Colorado, Hawaii, Idaho, Maine, Montana and Vermont -- and 382 cities, counties and towns have adopted resolutions expressing concern about the Patriot Act's potential infringement on civil liberties. Nearly 300 more resolutions are being considered, including 19 statewide resolutions in states as diverse as Wyoming, Tennessee and Massachusetts.
Among the sections due to expire at the end of the year that have drawn criticism are:
Sec. 201, which expands the number of federal criminal offenses for which wiretaps can be issued;
Sec. 202, which creates new wiretap authority relating to computer crime;
Sec. 203(b) and (d), which allow information gathered in criminal investigations, including wiretaps, to be disclosed to intelligence, immigration and national security officials;
Sec. 206, which allows "roving" wiretaps under the Foreign Intelligence Surveillance Act (FISA) that follow the target of the investigation to any telephone used. Sec. 206 does not include any requirement that only conversations involving the target can be listened to, a provision included in other roving wiretap laws;
Sec. 207, which permits FISA wiretaps to continue for as long as a year and extends the duration of physical search orders;
Sec. 212, which allows the government to demand records and content from communications providers without consent, notice or judicial review in an emergency;
Sec. 214, which allows the government to get the telephone numbers dialed to and from a particular phone as well as Internet "routing" information that may contain some substantive content of the communications, with minimal judicial review under FISA;
Sec. 215, which lets the FBI use FISA court orders to seize any "tangible thing," including medical, library, business and travel records, from a wide variety of institutions with minimal judicial review;
Sec. 217, which allows the interception of "computer trespasser" communications without a judge's assent;
Sec. 218, which allows criminal investigators to use espionage powers, which require little evidence of criminal wrongdoing, in cases when gathering foreign intelligence is only a "significant purpose" of the investigation, rather than the "primary purpose";