The enormous profits from the slave plantations were in part put into the industry that developed in the north, providing lots of the much-needed starting capital. The US wouldn't be where they're at today without the exploitation of slaves.

> The enormous profits from the slave plantations were in part put into the industry that developed in the north

The slave plantations could barely sustain themselves, and they started to war because they wanted to protect their fragile economy from competition.

The free north industrialized and economically buried the slave south. The rebel army didn't even have shoes - they went barefoot. The slave economy couldn't even produce shoes.

Of course there was trade and investment going back and forth between the states, after all, it was one country. But the idea that the wealth of the north depended on "enormous profits" from slavery is just not credible.

There's a reason that slavery died out in the northern states by 1800 or so. It didn't pay. It didn't produce enormous profits. It was an economic loser.

Slavery has failed every time it went up against free labor. It just can't compete.