The essential act of war is destruction, not necessarily of human lives, but of the products of human labor. War is a way of shattering to pieces, or pouring into the stratosphere, or sinking of the depths of the sea, materials which might otherwise be used to make the masses too comfortable, and hence, in the long run, too intelligent. Even when weapons of war are not actually destroyed, their manufacture is still a convenient way of expending labor power without producing anything that can be consumed. A Flying Fortress, for example, has locked up in it the labor that would build several hundred cargo ships. Ultimately, it is scrapped as obsolete, never having brought any material benefit to anybody, and with further enormous labors another Flying Fortress is built. In principle, the war effort is always so planned as to eat up any surplus that might exist after meeting the bare needs of the population...
It does not matter whether the war is actually happening, and, since no decisive victory is possible, it does not matter whether the war is going well or badly. All that is needed is that a state of war should exist.
-- George Orwell, 1984
This is the most rational explanation I have seen for, let's see... Vietnam, Iraq, Somalia, Bosnia, Afghanistan, Libya, and wherever else our handlers are trying to get us into.
In this environment, doublethink is a useful survival skill.