Great Britain did not commit an error by going to war against Germany in 1914. One can establish compelling reasons it was not a mistake by considering the taxonomy of Thucydides fear honor, and interest as contemporized by the Naval War Colleges Professor Genest as national security, credibility, and prosperity. First, an aggressive Germany, with a reasonable chance of quick victory against France, challenged Great Britains national security by compromising its military capability. Second, Berlins brazen violation of Belgian neutrality and antagonism toward France challenged Great Britains international credibility as its partners pleaded for help. Finally, a Germany engorged from territorial conquest in Europe creates a direct threat to Britains economic fundament and ability to compete globally. Though unprepared and probably able to reach a diplomatic accommodation with Germany, Britain chose the difficult but correct path in declaring war because it aligned with its national security interests, preserved its international credibility, and supported its long-term prosperity.