Nonsense, Democrats have always been what they were born as: the anti-Constitution, anti-Federalist faction of our Founders.
They voted "no" on ratification and became the party of nullification, slavery, secession and war against the United States.
When Democrats were in power, which was almost continuously from 1800 until secession in 1861, they ignored the Founders' Constitution to suit their own purposes, i.e., the Louisiana Purchase and SCOTUS Dred Scott decision.
Your claim that Democrats in 1840 were somehow more "conservative" than Whigs of the time was denied by Whigs who found plenty of "swamp" in DC under Democrat rule.
After the Civil War Democrats quickly went to work nullifying the 13th, 14th & 15th amendments and Southern Democrats especially cheered on the 16th and 17th amendments, expanding Federal power, providing foundations for the "Progressive Era" under Southern Democrat Wilson and New York Democrat Franklin Roosevelt, supported overwhelmingly in the Solid South.
So today's Democrats, especially their BLM & Antifa wings, are simply Democrats of the past in black-face.
Sure, you like to claim that Whig/Republicans were sometimes more Big Government than Democrats, but the great expansion in Federal government did not happen after the Civil War, it came more than 50 years later, beginning under Southern Democrat Wilson and flowering under FDR's New Deal, then Southern Democrat President Johnson's Great Society.
The fact is the big players in big government were all Democrats.
Ohioan: " I would recommend a book by Bill Rusher in the mid 1970s, The Making of the New Majority Party. Rusher, in that era was the "Publisher" of National Review, and was more pragmatic than some there, today."
I'm no expert on Rusher, but if as you seem to imply, Rusher here talks about Nixon's so-called Southern strategy, I would recommend to you D'Souza's new movie, "Death of a Nation" which, among other things, debunks that.
As for Jefferson's purchase of Louisiana? Yes he did cut the corner there, as to Constitutional authorization, but it was for exactly the opposite considerations to those behind LBJ's Great Society, or the Leftists winking at the open Southern border. It was, as he reported to Congress, to create a cultural buffer between the Founders' settlements & Hispanic America. (An American Immigration Policy)
As to Bill Rusher's strategy, it was basically post-Nixon, and led to the Reagan Democrats increasingly voting Republican.
You also appear to ignore the fact that the 14th Amendment was clearly an assault on the whole fabric of the Constitution, and was responsible for anchor babies, abortion, outlawing public religious expression, the removal of State Legislative checks & balances, school bussing & most of the rest of the egregious expansion of judicial activism. We obviously do not define "Conservatism" in the same way.
“I’m no expert on Rusher, but if as you seem to imply, Rusher here talks about Nixon’s so-called Southern strategy, I would recommend to you D’Souza’s new movie, “Death of a Nation” which, among other things, debunks that.”
Sure, because Dinesh knows so much more than the people who actually knew Nixon. Including some who designed the 1968 campaign and strategy.
“The two books I reviewed in the March 24 TAC, Alfred Regnery’s Upstream and Donald Critchlow’s The Conservative Ascendancy, both offer some interesting background on what became the Southern strategy. Regnery argues that National Review‘s Bill Rusher had outlined the strategy as early as February 1963, noting that (in Regnery’s words), “a conservative Republican with support in the Midwest and West could make inroads into the solidly Democratic South because of Southerners’ discomfort with the civil rights movement and thus eke out a presidential victory.”
https://www.theamericanconservative.com/2008/04/03/secret-origins-of-the-southern-strategy/
“Having made his intentions known, Nixon dialed up the charm. In January 1967 he invited Buckley, Bill Rusher (publisher of National Review), and other members of the conservative media to his sprawling Fifth Avenue apartment. There he exhibited his virtuosic command of foreign and domestic policy. Rusher remained unmoved — Rusher would always remain unmoved when it came to Nixon — but Buckley? There was no surer way to Buckley’s heart than a vigorous display of intellect and insight. As Neal Freeman, Buckley’s personal aide, recalled: “I knew when we went down the elevator, early in the evening, that Bill Buckley was going to find some reason to support Richard Nixon.” True, Nixon was no conservative, but the heart wants what it wants. And a smart, experienced, electable Republican was exactly what Buckley wanted in a 1968 candidate. More than a year before the election, he was recommending Nixon as the “wisest Republican choice.”
https://campaignstops.blogs.nytimes.com/2012/05/10/richard-nixons-model-campaign/
“In 1968, the political experts were all looking in the wrong place, just as they would do in 2016. “The young, the antiwar groups, the mass demonstrations,” Buchanan remembers. But Nixon’s men picked up a different signal: The center was being ignored and was there for the grabbing. “You could carve off the conservative wing of the Democratic party, populist and conservative—Northern Catholics and Southern Protestants we called them then—and bring them into the Republican party of Goldwater and Nixon.” A few liberal Republicans would flee, but the GOP would “wind up with the larger half of the country.” Out of this came Nixon’s 1972 landslide, on a scale unthinkable today: 60 percent of the vote, forty-nine states.
“To hear Buchanan sift through this, with his easy command of electoral numbers and voting trends, is to feel how thin and hollow our politics has become. “Northern Catholics” and “Southern Protestants” still exist in America, but you wouldn’t know it. They have been crowded into an undifferentiated blur—white and Christian, with no shadings. But Nixon’s men grew up in a denser geography of ethnic difference, full of prickles and thorns. They used terms like “lower-middle-class Irish Catholic”: Daniel Patrick Moynihan’s description of Buchanan, in a letter sent when both were working for Nixon. The two were ideological foes but, when it came to elites, of one suspicious mind.
“Later accounts would cast all this as a politics of bitter polarization, the marshaling of resentments and grievances. And indeed it was, to a considerable extent—”the whole secret of politics—knowing who hates who,” as Kevin Phillips, a lawyer and the master strategist of Nixon’s new majority, summarized it at the time. Phillips was a prodigy who at fifteen had begun working out the intricacies of shifting voter allegiances going back to the nineteenth century. Even younger than Buchanan, he had gone on to work for Nixon’s 1968 campaign and in his administration. His 1969 book, The Emerging Republican Majority, elevated voter analysis into a rarefied art. “American voting patterns are a kaleidoscope of sociology, history, geography and economics,” Phillips wrote. “The threads are very tangled and complex, but they can be pulled apart.” Phillips unknotted those threads in formulations like this: “The sharpest Democratic losses of the 1960–68 period came among the Mormons and Southern-leaning traditional Democrats of the Interior Plateau.”
http://buchanan.org/blog/pat-buchanan-tried-make-america-great-126773