Original sentence: All this means that nationalism in Korea, as elsewhere, is contested and varies depending upon the interpreter.However, many overseas Koreans distance themselves from such a definition.Since the intrusion by foreign powers in the late 19th century, Koreans have had to construct their identity in ways that pitted them against foreigners, tradition, and even themselves
Edited sentence: Since the intrusion by foreign powers in the late 19th century, Koreans have had to construct their identity in ways that pitted them against foreigners