Chikyuu Boueitai X

Yamato Koichi, a member of the Earth Defense Force, a secret organization that protects Japan from extraterrestrial lifeforms, believes that capturing the extraterrestrial lifeforms will lead to peace in the country. One day, Koichi meets a woman from the Extraterrestrial Life Force. She says that her homeland was destroyed and she came to Earth, and asks Koichi, "What do you want to protect Japan from?" This encounter leads Koichi to face the existence of unreasonable "evil" that nests within this country and cannot be punished by law.

(Source: Natalie, translated)