Uh, except the newly freed slaves weren't exactly in step with the south, and elected a number of Black congressmen belonging not to the Southern Democratic party, but to the Northern Republican Party. Congress was substantially more oriented towards the north after the Civil War than before it. The idea that the Civil War increased southern power is ludicrous.
Maybe you should learn basic US History. Or at least crack open Wikipedia. The 13th amendment banned slavery, the 14th concerns citizenship.
I'm African American, and yeah, it's my history. Your understanding of it is pretty bad. Like, White kid giving a book report in 5th grade for Black History month bad.