U.S. Representative T.U. Sisson of Mississippi gives testimony before the U.S. House Senate Judiciary Committee that the Fourteenth and Fifteenth Amendments were not adopted in accordance to the U.S. Constitution. The question of ratifications of Constitutional Amendments is a “Judicial Question” for the Federal Courts.
https://www.dirtyunclesam.com/pdf/Vlaidity_of_Fourteenth_and_Fifteenth_Amendments.pdf