It is interesting to me how the parties have sorted. As albaby pointed out, there used to be conservative Dems and liberal Reps. Both parties were a mix. The CRA of 1964 changed that. Not overnight, but pretty quickly. By 1968, Nixon's Southern Strategy was able to succeed. That's only four years. Today the parties are polarized. Not much mixing. Which is probably to the detriment of the parties (no dissenting voices, or at least very few...DINOs and RINOs, etc).

And this also is to the detriment of the voter because I believe the vast majority of voters fall somewhere in the middle. But the extreme factions of each party have enough sway to get polarizing figures through the primaries, and then in the general election you have to choose between a communist bleeding heart or a fascist racist (note: exaggeration for effect). How many times have we heard people say they don't like either candidate? If it were legal, I think there should be an extra box on the ballot "none of the above". If "none of the above" wins, then none of the candidates on the ballot can run again, and they have to select new candidates.

But back to the point, the Rep party of today is not the party of Lincoln, and the Dem party of today isn't the party of Strom Thurman. They've both changed, and neither offers much diversity of thought today.