Once formed, enemy images tend to resist change, and serve to perpetuate and intensify the conflict. Because the adversary has come to be viewed as a "diabolical enemy," the conflict is framed as a war between good and evil. Once the parties have framed the conflict in this way, their positions become more rigid. In some cases, zero-sum thinking develops as parties come to believe that they must either secure their own victory, or face defeat. New goals to punish or destroy the opponent arise, and in some cases more militant leadership comes into power.
A common justification for abuse of short term thinking is the fake perspective defense. The wise, but less confident guy says “hey are you sure we should be doing this?” And the smart, confident, but less wise guy says “of course. We did this last time, and the time before that, so why shouldn’t we do this again?” This is the fake perspective defense because there’s no reason to believe that 2 points of data (. last time plus the time before that) is sufficient to make claims about the future. People say similar things all the time in defense of the free market economy, democracy, and mating strategies. “Well, it’s gotten us this far, and it’s the best system we have”. Well, maybe. But if you were in that broken down Winnebago up to your ankles in gasoline from a leaking tank, smoking a cigarette in each hand, you could say the same thing.