I understand the expression to be shorthand for the principle that a person will defend a comfortable bunker position stubbornly and with main force. Changing t

I understand the expression to be shorthand for the principle that a person will defend a comfortable bunker position stubbornly and with main force. Changing the person's thinking will require significant energy and may exhaust your resources. Your adversary may die in that bunker. But there's an entire economic system that got your opponent to enter the position and believe in it.