This thesis revisits “Twenty Years’ Crisis” and considers what E. H. Carr means by “realism.” Since the 1990s, many works have challenged the stereotyped picture of a “realist Carr.” Now we know much about a “non-realist” Carr, but there still remain a lot of questions about Carr's “realism.” Contrary to the prevailing image of anti-idealism, Carr's “realism” is a “weapon” to demolish the inequalities between nations, and to rebuild a more equal order. <br> During the 1930s, the “idealists” such as Norman Angell and Leonard Woolf abandoned their optimistic beliefs in public opinion, and advocated the League sanctions against the fascist countries. Together with the pacifists, Carr criticized the League sanctions as a superficial solution, and insisted that the fundamental problem was the inequalities between the “have” and “have-not” countries. His criticisms toward the League were not a denial of the League itself. He criticized the “Coercive League,” which was hostile to the “have-not” countries, but supported the “Consultative League,” which functioned as a forum between the “have” and “have-not.” <br> Now we are in the long fight against terrorism. Global terrorism is, in part, a reaction to global inequalities. Carr's “realism” tells us that military actions alone never beat global terrorism.