What is Frederick Douglass' misconception regarding the North?

Before the events occurred in the attack on the arsenal of Harper's Ferry in October 1859, whose purpose was to arm the simultaneous rebellion of slaves in Virginia supported by Douglass but the whites of the south were convinced that the North was not willing to maintain liberties and their system of values in the confederation of states that was then the United States of North America. And so Douglass urged the Southern Democrats to remain in the Union, but they in turn named their own presidential candidate and threatened secession if the Republicans were victorious; most in the southern and border states voted against Abraham Lincoln, but the North supported him and won the elections. The separation of Texas in 1861 was imminent; Any incident that unbalanced the balance between slave and abolitionist states could provoke civil war. After Brown's incident, Douglass thought it appropriate to take refuge for some time in Canada in anticipation of being arrested for his alleged complicity in the arsenal assault and because he believed that Harper's attack on federal property would disrupt the American public against him.

Douglass met with President Abraham Lincoln in 1863 to establish what treatment would be given to black Unionist soldiers in the Civil War, as well as to Andrew Johnson on the question of his right to vote; the white abolitionists Lloyd and Wendell Phillips accompanied him in these efforts. However, at the beginning of the second half of the nineteenth century Douglass marked distances from the followers of Garrison on the subject of the Constitution of the United States

Definitely the Frederick Douglass misconception regarding the north was to believe that they would be in union with those of the south, since those of the south considered that North would not maintain a system of values, which is reflected in the separation of these and the nomination of candidates separately.