Glossarium: Aufzeichnungen der Jahre 1947-1951, p. 284, entry of 20 December 1949:
Mitleid beruht auf Identifikation; daraus machen die Mystiker des Mitleids, Rousseau und Schopenhauer, eine magische Identität. Aber das Mitleid, dessen man sich bewußt ist, kann nur Selbstmitleid sein und ist deshalb nur Selbstbetrug.
Compassion rests upon identification; the mystics of compassion make of it a magical identity. The compassion of which one is conscious, however, can only be self-compassion and is therefore only self-deception. (tr BV)
The old Nazi's cynical thought is that one deceives oneself when one thinks one is feeling compassion for another. What one is feeling, in truth, is compassion for oneself.
I wonder if Schmitt's thought is coherent. Compassion requires both identification and differentiation. On the one hand, I must identify with you in some manner and in some measure if I am to feel compassion for you. There must be some recognition of common humanity. If I have completely dehumanized you, like the Nazi the Jew, or the Commie the bourgeois class enemy, then there is no question of compassion. On the other hand, compassion as a conscious state is a state of me as distinct from you. So Schmitt is only half right. Compassion is at once self-compassion and other-compassion.
Example. A schoolmate of mine, Lee Didier, was killed at the age of 19 in a motorcycle accident. Ten years later, his mother Mabel was at my mother's funeral. Our eyes met and she gave me a look of compassion such as I have never experienced before or since. She had lost her only child; I had lost my only mother. It is not that Mabel felt my grief, which is impossible; she felt something analogous to my grief. She felt her own grief at the loss of a loved one and at the same time co-suffered (mit-leidet) my grief as an affect analogous to hers. Thus Mabel identified with me, but without any mystical or magical becoming identical with me. It was an identification presupposing differentiation, as opposed to an identification issuing in identity.
So I say Schmitt is wrong. He mistakenly thinks that identification entails identity. He does not see how there can be compassion along with differentiation. Failing to see this, he falls into the cynical view that compassion is at bottom compassion for oneself. If that were true, there would be no compassion.