States lost 407,316 military personnel, but had managed to avoid the extensive level of damage to civilian and industrial infrastructure that other participants suffered. The U.S. emerged as one of the two superpowers after the war. Unconditional surrender After the United States entered World War II, Franklin D. Roosevelt declared at Casablanca conference to the other Allies and the press that unconditional surrender was the objective of the war against the Axis Powers of Germany, Italy, and Japan. Prior to this declaration, the individual regimes of the Axis Powers could have negotiated an armistice similar to that at the end of World War I and then a conditional surrender when they perceived that the war was lost. The unconditional surrender of the major Axis powers caused a legal problem at the post-war Nuremberg Trials, because the trials appeared to be in conflict with Articles 63 and 64 of the Geneva Convention of 1929. Usually if such trials are held, they would be held under the auspices of the defeated power's own legal system as happened with some of the minor Axis powers, for example in the post World War II Romanian People's Tribunals. To circumvent this, the Allies argued that the major war criminals were captured after the end of the war, so they were not prisoners of war and the Geneva Conventions did not cover them. Further, the collapse of the Axis regimes created a legal condition of total defeat (debellatio) so the provisions of the 1907 Hague Convention over military occupation were not applicable. Post-World War II Since the end of World War II, no industrial nation has fought such a large, decisive war. This is likely due to the availability of nuclear weapons, whose destructive power and quick deployment render a full mobilization of a country's resources such as in World War II logistically impractical and strategically irrelevant. By the end of the 1950s, the ideological stand-off of the Cold War between the Western world and the Soviet Union had resulted in thousands of nuclear weapons being aimed by each side at the other. Strategically, the equal balance of destructive power possessed by each side manifests in the doctrine of mutually assured destruction (MAD), which determines that a nuclear attack by one superpower would result in a nuclear counter-strike by the other. This would result in hundreds of millions of deaths in a world where, in words