Clear distinctions

We've had a pretty hard time making Schmitt's clear distinction between "friend" and "enemy". He argues that every entity has to be one or the other; but we've wondered, does an enemy have to have a clear intent to hurt to be considered an enemy? Can global warming or a virus be an enemy? If we follow Schmitt's statement that an enemy is a similar force, than these examples are not enemies. But are they friends?

Schmitt tries to make friend/enemy an absolute, basic distinction like good/evil, beautiful/ugly - basically, black/white. He leaves little room for shades of gray. Enemies, though it is possible for a political entity to have good relations with them, are in some essential way different, and this difference makes war possible. Yet, Schmitt also states that enemies can change and become friends. Does Schmitt think that the essential nature of political enemies changes, so war is no longer possible? I think he's just covering a hole in his logic: that is, the friend/enemy distinction, just like the good/evil and beautiful/ugly distinctions, is subjective and subject to change.

If two states had been friends, and then gone to war, would Schmitt argue that they had actually been enemies on friendly terms? Or that the very nature of one country had changed so that the two were essentially different, thus making war possible? Are all foreign countries actually just enemies, with the possibility of war latent? How does one discern the nature of another nation, and how can you tell from that nature if war with a certain other country is possible or not?

I have to say, Schmitt befuddles me.