[user104658]

The US was cobbled together with heavy use of indentured servitude of Europeans - which is really just slavery with an out-clause.

It is worth mentioning though, as to not minimise things, that indentured servants were generally not mistreated in the same way that slaves were, nor were Irish slaves abused as badly as black slaves in the US. By the time slavery was abolished there was some next-level dehumanisation of black slaves and thus black people in general.