Of course the Whig party collapsed in the 1850s, and was replaced largely by the Republican Party, which in the aftermath of the panic of 1857--a seriously underlooked factor in the turmoil that followed--and the terrible war, brought in elements clearly to the Left of the Whigs. Thus the Democratic Party remained the more Conservative Party until the next great economic upheaval, the Panic of 1893, when the Conservative Democratic Administration of Grover Cleveland completely lost control of their own party to the easy money movement headed by William Jennings Bryan.
In the early 20th Century, each Party had a "liberal" wing & a "conservative" wing, but with the next great economic panic (the Great Depression) the Democratic Prty took a sharp turn to the Left, but still retained local Conservative politics, such as the Byrd Government in Virginia & similar traditionalists in South Carolina.
With Strom Thurmond's shift to the Republicans, in order to support Barry Goldwater, in 1964, the Republican surge to the right was underway, which led to several Republican victories, Conservative Supreme Court appointments, the election of Ronald Reagan, etc. (To understand the dynamics involved, 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.
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.