The north won the war. And now they get people from the losing states to fight their new wars for them. Same thing happened with e.g. the Romans getting auxilia

The north won the war. And now they get people from the losing states to fight their new wars for them. Same thing happened with e.g. the Romans getting auxiliary soldiers from conquered lands to fight for them, or the Brits getting soldiers from India to fight in the world wars. Typical imperialism.