What kept some african americans who could read and write from passing the literacy tests?

Southern state legislatures employed literacy tests as part of the voter registration process starting in the late 19th century. Literacy tests, along with poll taxes, residency and property restrictions and extra-legal activities (violence, intimidation) were all used to deny suffrage to African Americans.

confedracy

supported slavery

upheld the supremacy of federal laws

believed states should be able to nullify federal laws

union

wanted to abolish slavery

supported high tariffs

upheld the supremacy of federal laws