By all accounts, this battle is far from over, and could be one of the toughest wars that Washington has ever had to wage. That is because it is not between the militaries of powerful states -- as in World War II -- or between rival economic systems -- as in the Cold War.

To assess where the war on terrorism is headed, RFE/RL correspondent Andrew F. Tully spoke with Anthony Cordesman, a former intelligence analyst with the U.S. departments of State and Defense who now studies international affairs at the Washington-based Center for Strategic and International Studies.

RFE/RL: What is the true nature of the war on terror, and is it possible to estimate how long it may last?

Anthony Cordesman: None of us can estimate how long this struggle will be. It's really, primarily, an ideological struggle within Islam, particularly within the Middle East. [The United States is] really on the periphery of it. We are often described as a key target, but the fact is, these movements aren't struggling to control the United States, they're struggling to control Islam and Islamic countries, and particularly countries in the Arab world. So for anyone to try to predict when this is going to be resolved is simply totally unrealistic.

RFE/RL: So far, many countries, including the United States, have been fighting a concerted and, at times, coordinated war against terrorist groups, many of them believed to be loosely connected with Al-Qaeda. How much has this fight achieved in five years?

Cordesman: For all of the fighting, dealing with terrorism -- what we have accomplished in Iraq, in Afghanistan, and in supporting the counterterrorism efforts of many of the countries in the region -- while it's been useful, [it] has not weakened the ideological struggle or the various movements, which are Islamist extremist movements. And we are watching broader problems in terms of insurgency, of tensions between Sunni and Shi'ite, potentially Iranian-led efforts [to support terrorism], and groups which go far beyond Al-Qaeda.

RFE/RL: Therefore, do you expect a particularly long war?

Cordesman: A great deal depends on whether these movements are self-discredited. One problem that they face is that they can play on the tensions and problems -- the alienation within Islam and within Islamic countries. But what they advocate has no practical ability to govern, to be put into reality, to create effective economies. Their very extremism has often cost them support in the countries that they want to influence most, like Saudi Arabia.