How did social darwinists justify expansion?

The success of the American economy relied on new markets abroad.

Survival of the fittest resulted in strong nations controlling wear ones.

American expansion created stability in regions such as Latin America.

The correct answer is survival of the fittest resulted in strong nations controlling weak ones.

Social Darwinism is the belief that the strongest and most fit individuals will have success while those with less favorable characteristics will struggle. This was based on Charles Darwin's book Origin of Species. Even though the book was studying natural selection in terms of physical characteristics of birds, many people applied this concept to humanity.

This includes people who were in favor of American imperialism. These individuals who wanted the US to expand saw it as natural, as the weaker countries/regions the US would come to control were not fit for self rule. This would result in the US gaining territories like Guam, Puerto Rico, and Hawaii during the late 19th and early 20th centuries.