They've only recently become more Conservative.
The Democrats were taken over by two new factions ~ the former Commies and the African Americans. Both segments were smart to recast themselves as political factions rather than as full political parties and/or races.
“They’ve only recently become more Conservative.”
Just to clarify, when I use the term conservative, referring to American conservatives, I mean the resurgence of classical liberalism politically. In that respect, you are correct in saying the movement is new to American politics, rather revived. It has always been with us, but not like now, where people are beginning to see the dividing lines between 19th century clarity of values, and 20th century confusion.