The North was maybe a little more than an inch less racist than the South. It's just that the line of slavery being right or wrong went right through that inch. Institutional racism has come from everywhere, in particular by the power of the silent majority.

The Nixon Southern strategy was not to appease only Southerners. It was to appease the ignorant. Bigots with malice in mind.

It's worth listening to the Lee Atwater interview he didn't want released until he died. They had a vile plan, they put it into action, it was successful, and it's still happening. And such ideas and policies are far worse than just a word that begins with the letter n. https://www.thenation.com/article/exclusive-lee-atwaters-inf...

> My theory is that the government made them legal to appease Southerners after the Civil War.

It didn't; this is indisputable, because they existed and were legal, both in and out of the South, before the Civil War.

You could argue that they were not outlawed at the time chattel slavery was in order to mitigate the imposition on the South being done by the Civil War amendments (13-15), but that's implausible for a number of reasons, but most notably that being punitive was major feature of th Civil War Amendments, the cooling to punitive measures and accommodationist approach to the South didn't take long to appear after they were imposed, but it was a later thing.

> the evidence in terms of the Congressional record of the time

Specific citations would be welcome.

Emancipation was a political decision that was made for practical purposes.

Race baiting incited draft riots in the north. Low wage labor was very much threatened by the prospect of freed slaves migrating.

Prison labor isn’t a uniquely American institution and IMO was less about appeasing southerners and more about practical management of prisons.