The success of the north atlantic treaty organization (nato) immediately after world war ii is generally believed to have been dependent on the inclusion of in the organization.

The success of the Nato after world war II is generally believed to have been dependent on the inclusion of United States in the Organization

Back than, NATO was the main opponent of Uni soviet's influence. The inclusion of United States brought a great power within the NATO to oppose the communist influence

The reason why NATO was probably so successful (and what is commonly attributed to the reason for its success) was the fact that the United States were immediately added and included in this organization. This wasn't the case with the League of nations following World War I and was therefore a reason why it was unsuccessful.