Why did some Europeans oppose imperialism in the
late 19th century?

The anti-imperialists opposed the expansion because they believed imperialism violated the credo of republicanism, especially the need for "consent of the governed".

Explanation:

The anti-imperialists opposed the expansion because they believed imperialism violated the credo of republicanism, especially the need for "consent of the governed".

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explanation:

the second significant cause of the great migration was the desire of black southerners to escape segregation, known euphemistically as jim crow. rural african american southerners believed that segregation - and racism and prejudice against blacks - was significantly less intense in the north.