DiA makes a very important point:
[I]t's odd to see smart people talking as though the set of planks that make up each party's platform are bound together in some coherent way that flows from the two timeless essences of American political thought. It seems equally true to say simply that the mix of positions held by each party is the equilibrium response to the mix adopted by the other. As these debates over party identity show, this isn't necessarily the case in the short term, but the very identity to which purists want to hew is itself necessarily the product of the harsh evolutionary pressures of the electoral system.
"Republicanism" just means "the combination of views that were historically capable of securing a majority often enough to establish one of the two governing coalitions". Juggle the initial conditionsthe demographic facts or the issues that are salientand you almost certainly get a different coalition mix. I understand why one segment of the coalition would be eager to see their own views determine the direction of the party as a whole, but it seems silly to express this in terms of the language of authenticity.