Carl Schmitt is notorious as a prominent Nazi. But he wrote the 63 page The Concept of the Political, first published in 1932.
Schmitt starts by noticing that nobody has ever defined the political. And when they do, they tend to skate around, equating “political” is in some way with “state”
So what is the political? Schmitt sets forth the following definition.
The specific political distinction to which political actions and motives can be traced is the distinction between friend and enemy.
It is easy to compare the friend-enemy distinction to others, such as “good and evil in the moral; beautiful and ugly in the aesthetic”. But the political is different, because only in politics does disagreement lead to conflict.
[The enemy] is just the other, the stranger… so that in extreme cases conflicts with him are possible.
Of course, the enemy is easily thought of as "evil." But the "evil" need not be the enemy. The political, and its "friend-enemy" distinction, is independent of other distinctions.
Although the political is independent of other distinctions, people have tried to soften the friend-enemy distinction: in business, liberalism has softened the enemy into competitor. In a moral world there are hopefully only debate opponents. But, aside from hopes and aspirations, the friend-enemy distinction is something apart.
The political is the most extreme kind of human antagonism, and any antagonism "becomes more political the more it gets to the extreme point." And, of course, the more extreme that political antagonisms get within a state, the closer they get to civil war.
The word “conflict,” he writes, “does not mean competition” or “debate” or the routine “struggle” of life. It means killing.
The terms friend, enemy, and conflict… refer specifically to the real possibility of physical killing.
What about “religious war?” For Schmitt, the war is political, because the opposing religions experience each other as enemies. Same with the Marxist “class struggle.”
The state -- as political entity -- contains enormous power, waging war with human lives at its disposal to send out and kill other people. Thus, it tends to identify "internal enemies" as genuine threats that can escalate to actual civil war.
Combining the political with the moral is deceiving. The idea of a just war is nonsense, or political propaganda. So is the idea of "outlawing" war. If a people is determined to maintain its existential existence, then it must be prepared to decide for itself who is a friend and who is an enemy, and act upon this decision. But a people that has subcontracted its protection to another is not long for this world for "a weak people disappears" as a political entity.
The idea of a world state is nonsense. It would require a world in which nobody feared an enemy. And a world without enemies would be a world without politics. Thus the idea of the League of Nations (or the United Nations) as an association of humanity is nonsense.
There is an ongoing question of whether man is good or evil, but Schmitt asserts that political theories are clear on this
[T]he strange... observation remains that all genuine political theories presuppose man as evil... as a dangerous and dynamic being.
Indeed, it is by recognition of this that a thinker reveals himself as a political thinker.
Political thought and political instinct thus prove their worth theoretically and practically in their ability to distinguish friend from enemy.
The inability to determine the enemy is fatal, as inthe Russian nobility before the revolution, the "relativist bourgeoisie" and the ancien régime aristocrats of France as people that did not see who the enemy was.
Although "liberal thought" pretends to ignore the state and politics, in its actions liberalism smuggles power and politics in the back door. "The enemy is no longer called the enemy but in return he is set up as a threat to peace[.]"