The 14th amendment allowed ANYONE who was born inside the US the right to citizenship. With that mind they established the 15th amendment to allow ANYONE to vote.
Recap: Anyone was allowed to gain citizenship and vote which is how the 14th and 15th amendment were built on each other.
I think the main cause was slavery in the economy and society and there were pro slavery and free states so that didn’t work out
Answer:
Ruling Class Families in Rome