Throughout most of the nineteenth and twentieth centuries, most African Americans were prevented from voting in many Southern states despite the Fifteenth Amendment, which extended the right to vote to African American males. Southern states were able to take this action because

They passed the Jim Crow Laws.

Explanation:

Jim Crow laws was the widespread unofficial name of laws on racial segregation in some southern states during the post-Reconstruction period, that went from 1890 to 1964.

After the Civil War, which freed blacks from slavery, the federal government took steps to ensure their civil and political rights through the passing of the 13th, 14th, 15th amendments to the Constitution, and Civil Rights Acts of 1866 and 1875. In response, Southern Democrats passed local laws that severely restricted the rights of the black minority, as well as Indians who refused deportation to Oklahoma and remained under the jurisdiction of the US government in the southeastern states.

The beginning of the "Jim Crow Laws" era is considered to be 1890, when racial segregation on the railroad was introduced in Louisiana. By 1915, every southern state had passed laws that established segregation in educational institutions, hotels, shops, restaurants, hospitals, transportation, and toilets. There were also restrictions related to voting: electoral tax and literacy test, which applied only to blacks.

because mexico wanted to choose a centralized location

both are true, the congress does have the power to create banks, even if this power is not specifically described in the constitution, since there is nothing restricting it and there is power given to the congress to make "all laws which shall be necessary and proper". maryland was not allowed to tax a branch of the national bank operating there, and the supreme court decided that no state could. both of these topics were discussed in a decision of the mcculloch v. maryland case in 1819.