A technological or organizational edge in warfare (a "magic bullet" or perfect weapon) is always sought, but the advantage is never permanent. From 1945 to 1950, the U.S. thought it had the ultimate weapon, the A-bomb, but then Russia got one.
The fraternal twin of the magic bullet quest is "the last war" mentality, for both can distort a government's (or terrorist cell leader's) estimate of an emerging challenge. Wounds physical and social from World War I traumatized the French public, so France built the Maginot Line, the ultimate weapon for that "Great War."
There is a segment of the U.S. population that sees every U.S. war as "Vietnam," which is ludicrous but has emotional traction and hence political effects. Many Russians still view the West through a Cold War lens, and at times Vladimir Putin's sly government encourages their fears.
The War on Terror has given the U.S. military and intelligence services another lesson in anticipation and adaptation. America did not anticipate 9-11. That September day, al-Qaida attempted a "psychological blitzkrieg" when it used jumbo jets as ICBMs then followed up with a global propaganda campaign designed to magnify the terror (global media providing the siren on the Stuka).
That campaign asserted unshakeable international Muslim support for al-Qaida and tried to exploit American "last war" fears of Vietnam and Somalia. America, however, shook off the shock and adapted. The Predators circling al-Qaida's mountain hideouts target terrorists daily -- Osama bin Laden never anticipated fighting missile-armed robots. Predators still have magic, but no technological advantage ensures victory.
Germany's blitzkrieg was trumped after a long, hard slog that required blood, sweat, toil and tears. Al-Qaida's psychological blitz failed -- we are in another hard slog.
The wars the Nazis and al-Qaida launched both changed in ways their leaders never anticipated. The Nazis underestimated British, Russian and Yugoslav adaptation and perseverance. Al-Qaida completely misunderstood American capabilities and stamina, but also grossly misjudged its own political appeal. Moreover, the psychological edge of their September surprises eventually eroded.