Since World War I, America not only trained for the last war it fought, but also forgot or ignored the lessons of the past. We saw our enemy, attacked them, and then destroyed them. But this did not work in Vietnam, nor would it work in Iraq and Afghanistan where we didn't recognize our enemy, who reverted to guerrilla or insurgent tactics and techniques. While they shifted the gears of war, from conventional to unconventional and back, we still fought them the hard way, the wrong way. A few of us did not forget and changed rigid tactical doctrine. Then we used what we learned to fight that different enemy.