Central Intelligence Agency
The Central Intelligence Agency (CIA) is the United States' foreign intelligence agency, responsible for obtaining and analyzing information about foreign governments, corporations, and individuals, and reporting such information to the various branches of the U.S. government. It also maintains a vast covert military apparatus, which during the Cold War was responsible for a number of clandestine campaigns against foreign governments, leaders, and citizens. Its headquarters is in Langley, Virginia, across the Potomac River from Washington, D.C.
The Agency, created in 1947 by President Harry S. Truman, is a descendant of the Office of Strategic Services (OSS) of World War II. The OSS was dissolved in October 1945 but William J. Donovan, the creator of the OSS, had submitted a proposal to President Roosevelt in 1944. He called for a new organization having direct Presidential supervision, "which will procure intelligence both by overt and covert methods and will at the same time provide intelligence guidance, determine national intelligence objectives, and correlate the intelligence material collected by all government agencies." Despite strong opposition from the military, the State Department, and the FBI, Truman established the Central Intelligence Group in January 1946. Later under the National Security Act of 1947 (which became effective on September 18, 1947) the National Security Council and the Central Intelligence Agency were established.
In 1949, the Central Intelligence Agency Act was passed, permitting the agency to use confidential fiscal and administrative procedures and exempting it from many of the usual limitations on the use of federal funds. The act also exempted the CIA from having to disclose its "organization, functions, officials, titles, salaries, or numbers of personnel employed." The Central Intelligence Agency reports to U.S. Congressional committees but also answers to the President directly. The National Security Advisor is a permanent cabinet member responsible for briefing the President on pertinent information collected from all U.S. intelligence agencies including the National Security Agency, the Drug Enforcement Agency, and others.
Some critics have charged that this violates the requirement in the U.S. Constitution that the federal budget be openly published.
In 1996, the U.S. House Permanent Select Committee on Intelligence issued a congressional report estimating that the clandestine service part of the intelligence community "easily" breaks "extremely serious laws" in countries around the world, 100 000 times every year.  (http://www.thememoryhole.org/ciacrimes.htm)
The activities of the CIA are largely undisclosed. It undoubtedly makes use of the surveillance satellites of the National Reconnaissance Office (NRO) and the signal interception capabilities of the NSA, including the Echelon system, and the surveillance aircraft of the various branches of the US armed forces. At one stage, the CIA even operated its own fleet of U-2 surveillance aircraft. The agency also employs a group of officers with paramilitary skills in its Special Activities Division. Micheal Spann, a CIA officer killed in November 2001 during the U.S. invasion of Afghanistan, was one such individual.
In 1951, the CIA led the Anglo-American Operation Ajax, which in 1953 successfully deposed Mohammed Mossadegh as Prime Minister of Iran. In 1961, the CIA organized the Bay of Pigs Invasion of Cuba. When this failed, the CIA orchestrated a variety of plans to oppose Fidel Castro's regime, collectively known as Operation Mongoose. Between 1962 and 1975, the CIA organized a Laotian army known as the Secret Army and ran a fleet of aircraft known as Air America to take part in the Secret War in Laos, part of the Vietnam War. During the early 1970s, the CIA conducted operations to prevent the election of Salvador Allende in Chile. When these operations failed, the CIA joined in the planning of the coup which would overthrow Allende. In the early 1980s, the CIA funded and armed the Contras in Nicaragua, forces opposed to the Sandinista government in that country, until the Boland Amendment forbade the agency from continuing their support. This support resulted in a World Court decision in the case Nicaragua v. United States ordering the United States to pay Nicaragua reparations.
Defectors such as Phillip Agee have alleged that such CIA covert action is extraordinarily widespread, extending to propaganda campaigns within countries allied to the United States. The agency has also been accused of participation in the illegal drug trade, notably in Laos, Afghanistan, and Nicaragua. It is known to have attempted assassinations of foreign leaders, most notably Fidel Castro, though since 1976 a Presidential order has banned such "executive actions", except during wartime.
On November 5, 2002, newspapers reported that a car full of Al-Qaeda operatives in Yemen had been killed by a missile launched from a CIA-controlled Predator drone (a high-altitude, remote-controlled aircraft).
Support for foreign dictators and warlords
The activities of the CIA have caused considerable political controversy both in the United States and in other countries, often nominally friendly to the United States, where the agency has operated (or been alleged to). For instance, the CIA has supported various dictators, including Augusto Pinochet (see references below), who have been friendly to perceived US geopolitical interests, sometimes over democratically elected governments.
Often cited as one of the American intelligence communities biggest blunders, is the CIA involvement in equipping and training Mujahedeen fighters in Afghanistan, a radical Islamist group who would later form the core of the Al-Qaida network. Zbigniew Brzezinski, the National Security Advisor under President Carter, writes about this quite openly in his book 'The Grand Chessboard'.
Urged on by American conservatives, especially including influential foreign policy analysts at the Heritage Foundation, the CIA facilitated the so-called Reagan Doctrine, channelling weapons and other support (in addition to the Mujahedeen and the Contras) to Jonas Savimbi's UNITA rebel movement in Angola, thus turning an otherwise low-profile African civil war into one of the larger battlegrounds of the Cold War.
Criticism for ineffectiveness
The agency has also been criticized for ineffectiveness as an intelligence gathering agency. These criticism included allowing a double agent, Aldrich Ames to gain high positions within the organization, and for focusing on finding informants with information of dubious value rather than on processing the vast amount of open source intelligence. In addition, the CIA has come under particular criticism for failing to predict the collapse of the Soviet Union and India's nuclear tests or to forestall the September 11, 2001 attacks.
Conversely, proponents of the CIA respond by stating that only the failures become known to the public, whereas the successes typically do not become known for decades in the future.
One very successful 1982 CIA operation was made public on February 2, 2004 by William Safire of the New York Times, and was detailed in the book At the Abyss, by Thomas C. Reed. The Soviets were constructing a trans-Siberian petroleum pipeline, and required computer software to run the pumps, turbines, and valves necessary to operate the pipeline. Rather than develop their own, they set out to steal the required technology from the United States. The operation was detected by the French DGSE, and the information was passed to Gus Weiss at the CIA. Weiss ran a coordinated operation to alter the software so that it would function properly during testing, but fail in production. The Soviets did indeed put the software into production, and the pipeline did fail. This resulted in the largest non-nuclear explosion ever, detected from space by NORAD's early warning sensors.
The head of the CIA is given the title Director of Central Intelligence (DCI); ODCI means Office of the Director of Central Intelligence. The DCI is not only the head of the CIA but also the leader of the entire U.S. intelligence community and the President's principal advisor on intelligence matters.
The current DCI is Porter Goss, who was nominated by President George W. Bush on 10 August, 2004 and was confirmed by the Senate on 21 September. Goss inherits the post previously held by John E. McLaughlin, who served as interim director after longtime director George Tenet resigned on 3 June, 2004 and left the post on 11 July. Goss previously served as head of the House Intelligence Committee as a representative from Florida.
CIA operations in Iraq
According to some sources  (http://www.muslimedia.com/archives/features98/saddam.htm)  (http://www.globalpolicy.org/security/issues/iraq/history/1963cialist.htm)  (http://www.zmag.org/shalomhate.htm)  (http://www.informationclearinghouse.info/article2849.htm) the CIA appears to have supported the 1963 military coup in Iraq and the subsequent Saddam Hussein-led government up until the point of the 1990 Iraqi invasion of Kuwait. US support was premised on the notion that Iraq was a key buffer state in relations with the Soviet Union. There are court records  (http://www.gwu.edu/~nsarchiv/NSAEBB/NSAEBB82/iraq61.pdf) indicating that the CIA gave military and monetary assistance to Iraq during the Iran-Iraq War. The CIA were also involved in the failed 1996 coup against Saddam Hussein (see Iyad Allawi).
In 2002 an unnamed source, quoted in the Washington Post, says that the CIA was authorized to undertake a covert operation, if necessary with help of the Special Forces, that could serve as a preparation for a full-scale military attack of Iraq.  (http://www.cnn.com/2002/ALLPOLITICS/06/16/iraq.congress/)
It became widely known that the basis of the second Gulf War in 2003 was erroneous intelligence regarding Iraq's weapons capability. The term "weapons of mass destruction" (WMD) was famous around the world and was frequently used to deride those who had initiated the invasion, notably George W. Bush and Tony Blair.
The questions of whether CIA intelligence could have prevented the September 11, 2001, terrorist attack on the World Trade Center and the unreliability of U.S. intelligence on weapons of mass destruction in Iraq have been a focus of intense scrutiny in the U.S. in 2004 particularly in the context of the 9/11 Commission, the continuing armed resistance against U.S. occupation of Iraq, and the widely perceived need for systematic review of the respective roles of the CIA, FBI and the Defense Intelligence Agency. On July 9 2004 the final report of the US Senate Intelligence Committee states that the CIA described the danger presented by weapons of mass destruction in Iraq in an unreasonable way, largely unsupported by the available intelligence.  (http://www.nytimes.com/2004/07/09/national/09CND-INTEL.html?hp)
"Worldwide Attack Matrix"
In a briefing held September 15 2001 George Tenet presented the Worldwide Attack Matrix, a "top-secret" document describing covert CIA anti-terror operations in 80 countries in Asia, the Middle East, and Africa. The actions, underway or being recommended, would range from "routine propaganda to lethal covert action in preparation for military attacks". The plans, if carried out, "would give the CIA the broadest and most lethal authority in its history".  (http://www.washingtonpost.com/ac2/wp-dyn/A64802-2002Jan30?language=printer)
Other Government Agency or OGA is reportedly slang for the CIA.
A pejorative term for people who work for the CIA or other intelligence agencies is often 'spook'.