What's the core constituency?

Daniel Larison writing in a post about Club for Growth ruminates on the CfG's attacks on Mike Huckabee and states,

To the extent that their objections about Huckabee focused on his pseudo-populist appeals to working-class voters, they gave the impression that they were more interested in the corporate bottom line than the interests of core Republican constituencies.

I guess I'm confused here. Is there supposed to be a difference between "core Republican constituencies" and the "corporate bottom line?" From where I sit the two groups are pretty much layered right on top of each other. The GOP has been the party of the plutocrats for quite some time. They've cut a few deals with Dixiecrats and Evangelicals along the way but that was simply a way to advance the cause of the core GOP constituency group - the wealthy, the monied and corporations.

Conservatives like Larison end up in the GOP for much the same reason that Social Democrats like myself end up in the Democratic Party - there's really nowhere else for us to go in a 2 party, first-past-the-post electoral system. The Republican Party has never really been all that conservative in the Burkean sense, it's simply been more conservative than the Democratic Party and thus we see the misfit coalition of Evangelicals, Dixiecrats, conservatives, libertarians and the plutocrats that makes up the modern GOP.