Why did the United States choose the United Nations instead of joining the Axis during World War II?

After the outbreak of World War I, Americans have been playing the role of a neutral country. By 19 17, the two military groups were exhausted, but the Americans chose to send troops at this time. It can be said that they mean to fish in troubled waters. As the saying goes, when the snipe and the clam fight, the fisherman gains.

Americans not only earned a lot of plutonium, but also got rid of the control of European capital and accumulated a lot of foreign exchange. At this time, the United States has actually become the world's largest economy.

(Map of European Battlefield after World War I)

Militarily, the United States also tends to crush the old empire Britain, which can be seen from the comparison of warships owned by Britain and the United States in the Washington Treaty signed later.

In the two world wars, the United States, as the biggest beneficiary, played an important role in its rapid rise.

Although on the surface, Americans participated in World War II and joined the Allies because the Japanese provoked (attacked Pearl Harbor) first and the Americans retaliated later.

(Japan attacked Pearl Harbor)

But in fact, because of Japan's southward policy, the interests of Americans in Southeast Asia are threatened, which Americans cannot sit idly by. However, due to the influence of domestic isolationism, Americans have no excuse to go to war directly.

Japan's attack on Pearl Harbor can be said to be exactly what the United States wants, and the United States can take advantage of the situation to send troops to clean up the mess and successfully sit at the top of the United Nations.

Give me another reason why the United States does not join the Axis.

Germany's ambitions for expansion are endless. After France surrendered, Britain's power was further weakened and then promoted to the United States? European balance of power? The policy is undoubtedly a heavy blow. At this time, if the United States does not contain Germany's expansion momentum, it will be pushed out of Europe's sphere of influence by Germany, and the United States has no place in Europe. Therefore, there is an irreconcilable contradiction between their interests, so the United States will not join the Axis.