Final answer:
The primary argument of anti-imperialists was the moral and ethical opposition to the human costs and moral degradation of war, while secondary concerns included economic impact and racial prejudices. The Anti-Imperialist League, with notable members, championed the cause for liberty and self-determination.
Step-by-step explanation:
Main Argument of Anti-imperialists
The main argument of the anti-imperialists was that imperialism was morally wrong and against the principles of democracy and freedom on which the United States was founded. They contended that the human costs and moral degradation resulting from wars, such as the conflict in the Philippines following the Spanish-American War, did not justify the expansionist aims of the United States. Reports of atrocities and cruel actions towards Filipinos heightened the opposition to imperialism on ethical grounds.
Secondary Argument
As a secondary argument, some anti-imperialists, including labor leaders, were concerned about the economic and social impacts of annexation. They feared that the introduction of cheap labor from newly acquired territories would harm the domestic labor market. Others, such as E.L. Godkin, raised racial concerns about incorporating 'alien, inferior, and mongrel races' into the nation, which reflects the prejudiced attitudes of some members of the period.
The Anti-Imperialist League
The Anti-Imperialist League, which included prominent figures like Jane Addams, Mark Twain, and Andrew Carnegie, advocated for liberty and self-determination for all people, 'whatever race or color.' They worked to spread this message through meetings and publications, ultimately impacting the debate on American expansionism.