We are in a long war against radical Islamic terrorism. The struggle seems almost similar to the on-again/off-again ordeals of the past -- like the French-English Hundred Years War of the 14th and 15th centuries, or the Thirty Years War between Catholics and Protestants in the 17th century.
In these kinds of drawn-out conflicts, victory finally goes to the side that responds best to constant new challenges. And we've seen a lot of those since 9/11, when the United States was caught unaware and apparently ill-equipped to face the threat of radical Islamic terrorists hijacking our passenger jets.
But even when we adjusted well to the 9/11 tactics, there were new threats like suicide bombers and roadside improvised explosive devices that seemed to nullify American technology and material advantages.