We can speak of Karma not only in the case of individual persons, for man should not consider himself as a single being. If the individual were to rise even a few miles above the earth, the result would be the same as if the finger severed itself from the body.
If we penetrate into spiritual science we are literally forced to admit through this knowledge that we should not delude ourselves to the extent of insisting that we are single beings. This applies to the physical world and even more to the spiritual world. Man belongs to the whole world and his destiny is involved with that of the entire world. Karma touches not only the individual, but also the life of whole nations.
Source: Rudolf Steiner – GA 100 – Theosophy and Rosicrucianism: Lecture VII: The Law of Karma – Kassel, 22nd June 1907