Question

What did the author mean when he said "the cause of America" is "the cause of all mankind

Answer 1

When the author said "the cause of America" is "the cause of all mankind, he is refereeing o the worldwide plight of people under oppressive government and all of those individuals are struggling against them, the struggle for the cause of America is a symbolic statement for the struggle for the cause of humanity worldwide wherever the same kind of circumstances are found.