Final answer:
The Republicans proposed the 16th Amendment to grant voting rights to freedmen and build a powerful voting bloc in order to protect their interests and strengthen their political power.
Step-by-step explanation:
The Republicans proposed the 16th Amendment to protect their interests and strengthen their political power. After the Civil War and during Reconstruction, Republicans wanted to grant voting rights to freedmen in order to build a powerful voting bloc.
They saw extending the vote to African American men as a way to protect their rights and ensure their continued support for the Republican Party. The 16th Amendment was aimed at prohibiting states from denying or abridging voting rights based on race or previous condition of servitude.