Add Buchanan to the list as another "Dough Face" who bowed to the Slave Power. The same was true for control of Congress and the Courts. You are correct that from Jackson onward until the election of Lincoln, the Slave Power controlled the not just the Executive, but also the the Legislative and the Judicial branches.
Yet the declarations of the seven states that seceded even before Lincoln took office claimed nothing but abuse by the same Central Government that they had controlled for over 30 years since Jackson defeated J.Q. Adams.
They must have been engaging in self-abuse for 30 years? No wonder they were blind to the reality of what war would do to them. ;~))
Precisely speaking, the term "slave power" was used from almost the beginning of the Republic to refer to extra votes provided by the Constitution's 3/5 of slaves rule.
Indeed, it was "slave power" which first elected Thomas Jefferson President in 1800.
Without Jefferson's "slave power" President John Adams would have been re-elected.
It's the reason Jefferson was, at the time, called "The Negro President".
Indeed, that term "Negro President" for Jefferson adds a special cutting irony to slave-holder denegrations of Lincoln as a "Black Republican".
_ditto_ from post #279: "Add Buchanan to the list as another "Dough Face" who bowed to the Slave Power.
The same was true for control of Congress and the Courts.
You are correct that from Jackson onward until the election of Lincoln, the Slave Power controlled the not just the Executive, but also the the Legislative and the Judicial branches."
In fact, when you look at the list of Presidents from Washington through Buchanan, there was not one openly anti-slavery.
Indeed, very few elected Presidents did not themselves own slaves -- the Adamses, van Buren, Buchanan -- and except for John Adams, they were all Dough-faced Northern Democrats.
So Lincoln was the first President ever elected who was even mildly anti-slavery.
And minority Republicans only got elected because Southern Democrat "fire eaters" having ruled for generations, suddenly walked out and split apart their majority Democrat party.
In Congress the Southern Slave Power ruled through its majority Democrat party, which was very seldom and only briefly out-of-power in both houses.
In the Supreme Court, Slave Power domination was powerful enough to pass Dred-Scott (1857) by a vote of seven to two!
Only Massachusetts Whig Justice Curtis and Ohio Republican Justice McLean voted against Dred-Scott.
In fact, it was exactly this Slave-Power domination of Federal Government which drove Republicans to break-off and effectively destroy the old slavery-friendly Whig party.
Republicans feared, with good cause, that the next major Supreme Court decision would effectively make slavery legal in every state and territory.
So bottom line: the term "Slave Power" was not invented by Karl Marx, but rather by Americans themselves, at the time of the Founding, to refer to the extra votes constitutionally provided owners of human "property".
Terms like "Slave Power" and "Slavocracy" were later used by Republicans (1850s) to provide focus among "low information" Northerners who couldn't quite understand why they should not vote for Democrats.
;-)