Why is it that, in the USA, the Republican Party used to be the liberal party of the north and Lincoln while the Democrats were mostly more conservative southerners? How, when, and why did it happen that this situation reversed?

by SolarGorillaTortoise

I gather that it began to happen around the earlier part of the 20th century (I think) but it still seems confusing to me that they completely reversed like they have.

I have found some links here: http://www.reddit.com/r/AskHistorians/wiki/us_history#wiki_changing_role_of_republicans_and_democrats

This is probably the best answer I've found so far: http://www.reddit.com/r/AskHistorians/comments/yczua/can_someone_address_a_brief_history_of_democrats/