I hope this hasn't been asked before, but if it has, please direct me there.

I was listening to the 10 American elections podcast discussing the 1964 American presidential election, and the speakers were discussing the split between conservative and liberal Republicans at that time (Goldwater and Rockefeller respectively). I grew up in the 1980s and never heard of a "liberal Republican" -- parties in my mind have always reflected a political ideology. If you were a conservative you were a Republican, a Democrat if you were liberal. There were "wings" and centrists to each party, but the fundamental split between the parties was ideological.

So my question is, why, before 1964 would somebody be a Democrat or a Republican if party loyalty wasn't based on a particular philosophy of government?

Thanks.