Question

The Republican Party became strong in the South, in part because

millions of Southern African American men became voters.
the party did not require a loyalty oath in order to vote.
many white Southerners attended the state constitutional conventions.
all of the former Confederate states had met the requirements to rejoin the Union. The Republican Party became strong in the South, in part because

millions of Southern African American men became voters.
the party did not require a loyalty oath in order to vote.
many white Southerners attended the state constitutional conventions.
all of the former Confederate states had met the requirements to rejoin the Union. @History

Answer 1

Millions of southern African American men become voters.

Answer 2

Until Jim Crow laws kicked into effect all over the South. That is when Southern politicians tried to use laws to prevent African Americans from voting (such as poll taxes, or literacy tests). This in effect removed the vote from African-Americans.