Because we are isolated perhaps he feels far less vulnerable than other world leaders to surrounding circumstances.

from Wolin Politics and Vision, discussing machiavelli

The symbol of man’s illusions was the armed fortress. The fortress, in all of its seeming solidity, dramatized the false hope that there could be points of fixity, anunchanging basis of political and military security, in a restless world. But thereis a further lesson to the symbol. Deceived by the impressive exterior of his fortress, the ruler comes to believe himself invincible and is tempted into cruel and extreme acts. The illusion of security thus releases the psychological springs of ambition and domination. This example gives point to one of the principles of the new science: vice, in a political sense, is often the function of illusion,virtue the product of clear-sightedness