Hetalia: Axis Powers - Paint It, White! (2010) Anime Watch

Earth is under attack by extraterrestrials and a group of eight people meet to decide on a course of action. Although America wishes to fight, England and France are still recovering from an earlier conflict, Japan is indecisive, and Italy decides to wave a white flag.

The meeting ends without consensus, with each faction facing the aliens in their own way. However, all military actions prove useless and the white flag is ignored.

Reluctantly, the eight reconvene and come to the conclusion that the only way to discover the aliens' weakness is to infiltrate their mother-ship