Answer:
The government of an area needs to support an initiative for the initiative to be able to succeed. If the government does not support the initiative or if it sees it as a threat, the initiative simply cannot prosper.
This was the same with the Civil rights movements for African Americans in the early 1900s, it did not have the support of Southern governments as these governments were not sympathetic to the plight of African Americans.
If a government is not supporting a noble initiative, the people can remove the government but in this case, African Americans could not move these governments because they were restricted from voting by the poll taxes and literacy tests.
They therefore could not put in a government that would support civil rights but were instead stuck with a government that actively opposed it and could not be removed because those poll taxes and literacy tests protected them from those that they were oppressing.
Poll taxes and literacy tests therefore went a long way in undermining the Civil rights movement.