The legacy of the league of nations was that

The absolute necessity of an international organization for settling disputes between countries was real, but also, it became evident that an organization of that kind would be powerless and useless unless the United States took part in it.

the answer to fill in the blank in this question would be the word resource, it is defined as the money, material or people (since human resource is a very valuable good) that a company or a person has at disposition (meaning they can use the resource as they see fit), to be able to complete a task or achieve a goal.  

gender discrimination race discrimination hard