Southern states sometimes used a grandfather clause to allow them to

Southern states sometimes used a grandfather clause to hinder African-Americans from voting and let the whites to vote.

Explanation:

The Grandfather clause is defined as "a clause exempting certain pre-existing classes of people or things from the requirements of a piece of legislation"

It enacted for voting purpose on Tuesday, 2nd of August, 1898 as a legal or constitutional mechanism passed by seven Southern states during reconstruction to deny franchise (the right to vote in political elections) to black Americans.

hold on ill go look

necessary and proper clause. the congress shall have power to all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states, or in any department or officer thereof.