[BroJoeK]

Ditter: "I am still having trouble with “dough” meaning a nervous “doe” deer, but whatever you say."

Yet further googles turned up this link with a great explanation.

The original discussion came from Theodore Dwight Weld's 1839 book: American Slavery As It Is: Testimony of a Thousand Witnesses.
Weld wrote:

" 'Doe face,' which owes its paternity to John Randolph, age has mellowed into 'dough face' – a cognomen quite as expressive and appropriate, if not as classical."

But Weld and all other historians commenting on this question end up punting and straddling both sides.
Leonard Richards (Slave Power) put it this way:

"Not everyone understood Randolph’s reference, and no one dared to ask for an explanation.
A few apparently thought the sardonic Virginia aristocrat had a female deer in mind and the word he used was doe.
Others thought he was referring to a child’s game where children put dough on their faces, worked it into strange configurations, and then looked at their reflections.

"Whatever Randolph had in mind, his words stuck."

The key point is that "Doughface" was a derogatory term, used by Southerners to insult Northerners who were trying to please them by giving into Southern demands.

Of course, in my context on this thread, I mean nothing of the sort.
Instead, I mean Northerners who share the South's commitment to true conservative principles.
So I'm not trying to insult anyone, but perhaps to rehabilitate the term "Doughface" in a modern, positive sense.

[Ditter]

You have certainly done some excellent sleuthing. So if I call you a doughfaced northerner and you call me a redneck Texan, we will neither one be insulted! :D

[x]

Instead, I mean Northerners who share the South's commitment to true conservative principles.

Maybe it's the other way around. Instead of a Wallace or a Thurmond, someone with deep Southern roots, Southern states are going for guys from Pennsylvania (though both have Southern ties).

Newt Gingrich or Rick Santorum as a spokesman for "Southern conservative principles" may be an indication of how much things have changed in fifty years or so. Of course, the fact that these guys are a lot less likely to carry states like Pennsylvania does tend to cloud things.