Back in the 1840's Chief Justice Roger Taney was generally regarded as a worthy successor to his famous predecessor in that role, John Marshall.
Though a Jacksonian Democrat from a wealthy slave-holding family in Maryland, Taney had actually taken the unusual step of emancipating his own slaves and providing pensions for those too old to seek their own employment.
Nonetheless, Taney remained an ardent defender of (Southern) States Rights in general and the "Peculiar Institution" in particular; and as the sectional divide over slavery grew in the 1850's with its potential spread into the vast new territories recently seized from Mexico, he decided to try and "resolve" the issue definitively with his own brand of judicial activism.
That case of course was the infamous Dred Scott decision of 1857, in which SCOTUS ruled in a 7-2 verdict that the petitioner Dred Scott not only should remain a slave in Missouri, despite having lived with his former master in both the Free State of Illinois and the Free Territory of Minnesota before returning to Missouri.
Not stopping there though, Taney went on to rule that since the US had supposedly been founded as a "white" republic, no one with any "black" ancestry could rightfully be a citizen of said US at all, regardless of whether they were free or slave -- or as Taney so delicately put it, "the black race was so inferior to the white race that they have no rights the white man is bound to respect."
Up to this point, the SCOTUS ruling could still have been at least reluctantly accepted by a substantial majority of mid-19th Century Northerners, but even that ahistorical racist rant wasn't enough for Taney, who was just getting warmed up.
Really letting his partisan freak flag fly, Taney then crossed the Rubicon by declaring that Congress had no right to exclude slavery from any of the Federal territories -- rendering the Missouri Compromise of 1820 (which had set aside all land to the north and west of Missouri in the Louisiana Purchase as Free Territory from which slavery would be legally prohibited) retroactively unconstitutional!
This was a bridge way too far beyond what the newly formed Republican Party was prepared to accept, or even most Northern Democrats for that matter -- since the Dred Scott decision invalidated the Popular Sovereignty doctrine of their 1854 Kansas-Nebraska Act just as much as it did the Missouri Compromise.
By being so nakedly partisan in favor of slavery, Taney guaranteed his ruling would never be accepted in the North (or West), and the countdown toward secession and civil war began in ernest.
So for those wondering why the "legality" of secession was never brought before SCOTUS during the nearly 4 months between South Carolina's initial proclamation and the firing on Fort Sumter, the answer should be obvious -- none of the seceding states recognized SCOTUS as having any authority over them once they made their decision to withdraw from the Union, and no one in the North would give any deference to a ruling from such a biased and thoroughly discredited court.
And when Taney tried to intervene on his own by placing legal roadblocks on Lincoln's prosecution of the war (Ex parte Merriman) by declaring the suspension of habeas corpus in 1861 Maryland unconstitutional, Lincoln simply ignored his ruling by invoking the doctrine of Nonacquiescence, which had first been used by Andrew Jackson in response to an earlier 1832 SCOTUS ruling in favor of the Cherokee vs Georgia. Jackson is supposed to have stated "John Marshall has made his decision, but now let him enforce it" -- indicating he had no intention of complying.
Perhaps it's time for Biden to summon his inner Lincoln and publicly declare that this latest SCOTUS ruling regarding Presidential Immunity is so obviously wrong in its legal reasoning and corrupt in its motive that it necessitates a wholesale restructuring of SCOTUS in his next administration, and use the argument of Nonacquiescence in the meantime as a major part of his reelection campaign.