The basis is the last 60 years or so. Looking earlier than the seventies or so and the parties are recognizable in name only. There's been a pretty radical shif

The basis is the last 60 years or so. Looking earlier than the seventies or so and the parties are recognizable in name only. There's been a pretty radical shift in party ideologies, particularly identity politics, over the last century. Republicans of half a century ago would have hanged the modern republican party politicians as traitors and seditionists.