I could say "The Military-Industrial Complex" and be done with it, but that would leave many people eager to flame me because they think I'm a conspiracy theorist due to the fact that I used one of the phrases on their list of code words.
However, I'll explain.
a) Widespread nationalistic climate amongst the population.
b) Jingoistic xenophobes voted/otherwise get into power.
c) "Someone out there has something we want, so let's bomb their asses."
d) The newly-elected Jingoistic government buys lots of military hardware from corporations, a.k.a. the "Military-Industrial Complex."
e) Profit flows towards said corporations, who in turn funnel huge amounts of money through campaign donations to politicians who pledge to swing some business their way in the form of starting BS wars.
f) Repeat.