They’ll have lots of people under their thumbs... millions of them. And since white liberal elites want to welcome the third world into their country they could have billions of people under their thumbs.
I’m guessing that in short order liberal elites wil do the old commie trick and start murdering their citizens. So part of the deal has to be a Wall between the two countries. They can shoot people trying to escape - like commies did with the Berlin Wall... But since people in liberal land will have been totally disarmed, I’m guessing keeping their thumbs on everyone will be fairly easy. North Korea does it. Liberals can bond with North Korea and Cuba to learn ways to keep citizens in line.