That is likely because they can’t produce anything. But the two nations would have to set up trade pacts and we would sell foot to the communist nation.
They could easily take down all borders on Day 1 and get flooded with poor, illiterate peasants all demanding their “fair share.” Of course a lot of blacks would be demanding reparations which the new government would have to pay.
It would be a failed third-world sh1thole within a year — the same way the “palestinians” destroyed all the greenhouses gifted to them by the Israelis and every previous colonial state in Africa.
What a fine neighbor that would be.
Seems like a less dangerous version of the status quo: prosperous Red States adjacent to declining & failed Blue States, with the people running the third-world Blue States wanting to loot the Red States, and remake the entire federal republic in their own "sh!t-hole" Blue State image. At least there would be a meaningful border, and a sound legal basis for societal self-defense. If Nancy Pelosi showed up on your doorstep, you could have her arrested for trespassing & deported...
;^)