Bruce Hoffman's testimony to the Senate Foreign Relations Committee on July 18, 2006:

Islam and the West: Searching for Common Ground: The Terrorist Threat and the Counter-Terrorism Effort
Today, al Qaeda is also frequently spoken of as if it is in retreat: a broken and beaten organization, incapable of mounting further attacks on its own and instead having devolved operational authority either to its various affiliates and associates or to entirely organicallyproduced, homegrown, terrorist entities. Nothing could be further from the truth. Al Qaeda in fact is on the march. It has re-grouped and re-organized from the setbacks meted out to it by the United States and our coalition partners and allies during the initial phases of the global war on terrorism (GWOT) and is marshalling its forces to continue the epic struggle begun now some ten years ago. Al Qaeda is now functioning exactly as its founder and leader, Usama bin Laden envisioned it. On the one hand, true to the meaning of the Arabic word for the “base of operation” or “foundation”——meaning the base or foundation from which worldwide Islamic revolution can be waged (or, as other translations have it, the “precept” or “method”)—and thus simultaneously inspiring, motivating and animating, radicalized Muslims to join the movement’s fight. While, on the other, continuing to exercise its core operational and command and control capabilities: directing the implementing terrorist attacks... Qaeda’s capacity to continue to prosecute this struggle is a direct reflection of both the movement’s resiliency and the continued resonance of its ideology. Accordingly, if the threat we face is constantly changing and evolving, so must our policies and responses be regularly reviewed, updated and adjusted. In this struggle, we cannot afford to rest on past laurels or be content with security that may have proven effective yesterday and today, but could likely prove inadequate tomorrow given this process of terrorist change and evolution.

Al Qaeda’s “operational durability” thus has enormous significance for U.S. counterterrorism strategy and policy. Because it has this malleable resiliency, it cannot be destroyed or defeated in a single tactical, military engagement or series of engagements—much less ones exclusively dependent on the application of conventional forces and firepower. To a significant degree, our ability to carry out such missions effectively will depend on the ability of American strategy to adjust and adapt to changes we see in the nature and character of our adversaries.