system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How come the south was democratic in Lincoln's time but Republican now?
gpt
The Civil Rights Act and Nixon's Southern strategy in 1968. 

A Democrat Lyndon B. Johnson signed the Civil Rights Act signing away the racist white south, and Nixon promised to battle the liberal supreme court and took the South from the Democrats.  It has been that way ever since but likely not really due to race related issues anymore. 

 The South used to be filled with "yellow dog democrats" as in they would rather vote for a yellow dog than a republican.  Funny how things turned out.