"They are constantly under assault. Their financial lifelines have dried up. Their weaponry has dried up. Anytime your leader is hiding in a cave, it is hard to say that you are in the same strong position you were in when you were living in a mansion," noted Pletka.
Many experts agree that the "war on terror" has been successful in degrading al-Qaida's operational capabilities.
One of those is Brian Jenkins, a leading authority on terrorism working for the RAND Corporation. But he says the U.S. and its allies have not been successful in denting al-Qaida's determination to continue its "jihad," or holy war, against the West.
Given the international scope of the terrorist threat, Jenkins and others believe the "war on terror" will go on for a long time. Experts say a successful outcome will involve a combination of vigilance at home and increased international cooperation.