Kufr is denial of Allah or any of the teachings of Islam. The belief that the Taalibaan or any Muslim force was or can be defeated by the sophisticated military power of the kuffaar superpowers, is kufr.
Muslims of shallow understanding and lacking in sound knowledge of the Deen believed that the Taalibaan were defeated by the awesome and awful airforce of the U.S.A. and its superior weaponry of the most advanced and devastating kind. This belief is kufr.
Such a belief implies that Rabbul Aalameen—Allah, The Creator of the universe, Who had aided the small band of Sahaabah at Badr, has—Nauthubillaah! ----become impotent, lacking in power to aid the Mu'mineen against a 'super power possessmg the most dreadful kind of weapons. This implication is kufr without any doubt.
The very same Rabb Who gave victory to the small bands of Sahaabah, exists today with all His power intact. The cause of our defeat is our transgression which has reached kufr dimensions. Our rebellion against the Shariah and Sunnah is the disease which brings humiliation and defeat to the Ummah. The army, airforce and navy of America and of all the kuffaar states cannot vanquish this Ummah if it regains its moral and spiritual fibre.
Small and weak groups of Mujahideen in Iraq have exposed the weakness of the American military which lacks fighting ability.