1.2 billion people in South Africa and around 500 million in South America. How many of those could have their life style enhanced by given a chance in the US. We could support them by increasing taxes to 80+% . Just enough to buy food and cut waste spending like on video games. Open borders, how many is enough and who are the unluckys that miss out and starve we'll we game.
Keep in mind that it starts out as 1.2 billion in Africa and 500 million in South America. If we feed them completely and they get comfortable they are going to breed more and now costs could easily double. The only way they are going to improve for those countries is if they become more educated, responsible and stop putting up with criminals.