The big lie that Donald Trump actually won the 2020 election has nothing on the big lie that the Confederacy was not founded for the sole purpose of perpetuating and expanding slavery. Confederate leaders were not apologetic about why they rebelled against the United States. They did so because they feared, without any great foundation, that Congress or the newly elected Abraham Lincoln would abolish slavery.

They also resented what they feared was a push to stop them from expanding their system of slavery into the West, and here their fears were more well founded.

In fact, digging into history, it's informative to look at how Confederate thinkers and leaders wrote about plans to expand slavery south (into Mexico and even into South America, by annexing territory against the will of the people who already lived there) once they had won their war of rebellion.

Confederate leaders certainly understood that the sole purpose of the Confederacy was perpetuating and expanding slavery.