Now wait a minute, if there were only whites, then slavery would never have existed! and thus the Republican party wouldn't have either...
If the South would have still had plantations in a whites-only America, I could see the Anglo-Saxon whites enslaving the Mediterranean and Eastern European whites.
Um, why would Mediterranean and Eastern European whites immigrate to a country that would enslave them?
They wouldn't do it voluntarily. The Anglo-Saxons would bind them and force them to come over here. I think back in the Middle Ages Europeans actually enslaved one another, before they discovered the African slave trade.
No, they didn't. They had serfdom in medieval Europe, not slavery. And they would have been far better prepared to fend off attempts at forcing their enslavement than the Africans were.
Nah, it's not like Africans were invaded by whites, black people in Africa sold their war prisoners to visiting white people. Whites were just new customers in the long-lived African slave trade.