In the broadest terms, acts of terrorism have generally been attributed to groups with political goals. But in the last part of the 20th century, a new and dangerous phenomenon arose. Some governments started using terrorist groups as surrogates to fight for their political aims.

Al-Qaida leaders, Osama bin Laden and Ayman al-Zawahri

When it comes to terrorism, world attention is quite naturally focused on groups like al-Qaida. But as Vince Cannistraro, former chief of the Central Intelligence Agency's Counterterrorism Center, says, until the advent in the 1990s of groups like al-Qaida -- which operate independently -- U.S. attention and resources were primarily directed at state-sponsored terrorism.

According to Cannistraro, "State-sponsored terrorism is certainly the kind of terrorism that the United States was most familiar with. And we had made a very difficult transition from dealing with state-sponsored terrorism, which mostly involved secular groups, to understanding the nature of extreme religious-oriented terrorism against us. There was a complete change in the mindset. And so we took a long time before we really understood the dangers presented by al-Qaida."

Broadly speaking, a state sponsor of terrorism is typically a country that uses terrorist groups as a kind of proxy for actions or policies it does not want to leave its fingerprints on. Former CIA officer Michael Scheuer says the key example is Iran's backing of Lebanese Hezbollah. He says, "State-sponsored terrorism came in the middle-1970s, and then, really, its heyday was in the 1980s and early-'90s. And typically, the definition of a state sponsor of terrorism is a country that uses surrogates as its weapon to attack other people. The primary example to this day is Iran and Lebanese Hezbollah. Hezbollah, in the nomenclature of the discussion, would be the surrogate of Iran."

Repercussions for Countries that Harbor Terrorists

The Bush administration has taken that definition a step further. In a speech at Kansas State University in January, President Bush reiterated that any country that gives sanctuary to a terrorist group -- even if the government does not actively back or utilize the terrorists -- will be considered a state sponsor of terrorism. He said, "I laid out a doctrine, and it said: 'If you harbor a terrorist, you're equally as guilty as the terrorists.' The reason I said that is because I understand that a terrorist network can sometimes burrow in society and can sometimes find safe haven from which to plot and plan. The perfect example of that was Afghanistan."

The United States issues an annual list of groups and countries it deems to be state sponsors of terror. Larry Wilkerson, who was Chief of Staff to Colin Powell when he was Secretary of State, says compiling that list is an intricate process.

"It's a very thorough process," says Wilkerson. "It's heavily vetted. It's looked at from all ramifications, as you might imagine -- political ramifications, financial ramifications, social and cultural ramifications. And it's not a light decision to put someone on the terrorist list."

Who Are the Sponsors?

Currently, six countries are on that list: Cuba, Iran, North Korean, Syria, Libya and Sudan. Iraq was on the list, but was dropped from the list after the U.S.-led coalition toppled Saddam Hussein.

The United States aggressively tried to demonstrate a link between Saddam Hussein and al-Qaida as one of the rationales for attacking Iraq. But Larry Wilkerson says there was no evidence of an al-Qaida-Iraq alliance. "As a matter of fact, the evidence I've seen would be quite contrary to that. In other words, Saddam Hussein had his agenda and al-Qaida had its agenda, and those two agendas were incompatible. And so if there was any contact between them, it was a contact that was rebuffed rather than a contact that led to meaningful relationships between them," says Wilkerson.

Once on the U.S. terrorism list, it is hard to get off. Iran and Sudan, who it was thought might come off the list, are staying on, according to U.S. officials. Richard Armitage, who was the Bush administration Deputy Secretary of State until last year, says a country has to do more than just publicly renounce terrorism to get off the list.

"It gets off when it eschews terrorism and when its actions follow its words," says Armitage. "In the case of Libya, for instance, they wouldn't get off the list until it resolved the questions lingering from the bombing of the Pan Am airliner. So it's a complicated procedure. But the bottom bedrock, sort of bottom line, is that you have to renounce terrorism as an instrument. And then, if there are residual issues such as retribution to families or recompense for families, things of that nature, then those have to be resolved as well."

Former CIA officer Michael Scheuer says Iran and Syria are considered to be the most

Hezbollah rally

active in sponsoring terrorism -- Iran for its backing of Hezbollah and Syria for aiding Hezbollah, Hamas, and other Palestinian groups attacking Israel. Syria has been implicated in the assassination of several key political figures in Lebanon, including former Prime Minister Rafik Hariri.

Ex-CIA counterterrorism chief Vince Cannistraro notes, however, that Iran offers help to anti-terrorism efforts when it chooses to do so. He says, "Iran has been cooperative with the United States in the past on other forms of terrorism, particularly al-Qaida-sponsored terrorism. When al-Qaida fled Afghanistan after the invasion of Afghanistan by the United States, a number of them went to Iran, and many of them were incarcerated by the Iranians. The Iranians sent maybe 100-to-200 of these people back to their home countries, Saudi Arabia and Egypt, et cetera."

Of course, different nations have different ideas about what constitutes a state sponsor of terrorism. India has lambasted Pakistan for what New Delhi says is Islamabad's sponsorship of militants carrying out attacks in Indian Kashmir. India calls them terrorists; Pakistan calls them freedom fighters.