Which is not a method southern state ledgislature use to make it difficult for southern blacks to vote?

Southern state legislatures historically employed various methods to suppress Black voting, including literacy tests, poll taxes, and understanding clauses. However, one method not used for this purpose would be the implementation of automatic voter registration, which aims to increase voter participation rather than restrict it. Instead, automatic voter registration is designed to simplify the voting process and make it more accessible for all eligible citizens.