This reactionary simplistic view how history whitewashes what the North's position really was.

1) You missed: It was slavery (The states' rights to not enforce the fugitive slave act)

2) The south's position was unarguably[0] defined by their view on slavery. However, the north's position was far less clear cut. There was certainly an abolitionist movement in the North; but even during the civil war, they did not control northern politics.

Despite the failure of northern states to enforce the fugitive slave act, there was still a general willingness in them to tolerate the existence of slavery the southern states.

Unlike the confederacy, the stated aim of the US during the civil war was explicitly not the abolition of slavery, but rather the preservation of the union. I believe their actions leading up to the civil war were consistent with this. However, if you doubt the honesty of the stated goals of the North, you can look instead at to the slave states that stayed with the union: Maryland, Delaware, Kentucky, and Missouri. Since I am from Maryland, that is the state whose history I am familiar with. When it rejected secession, the Maryland legislature passed a resolution stating:

> The General Assembly of Maryland have seen with concern certain indications at the seat of the General Government, of an interference with the institution of slavery in the slave-holding States, and cannot hesitate to express their sentiments and those of the people they represent, in regard to a policy so unwise and mischievous. This war is prosecuted by the Nation with but one object; that, namely, of a restoration of the Union, just as it was when the rebellion broke out. The rebellious States are to be brought back to their places in the Union, without change or diminution of their constitutional rights. In the language of the resolution adopted by both Houses of Congress at its extra session in July last, with remarkable unanimity, this war is declared to be prosecuted not “in any spirit of oppression, or for any purpose of conquest or subjugation, or purpose of overthrowing or interfering with the rights or established institutions of those States, but to defend and maintain the supremacy of the Constitution, and to preserve the Union, with all the dignity, equality and rights of the several States unimpaired, and that as soon as those objects are accomplished, the war ought to cease.”

> The objects and purposes of the war thus impressively declared, are those alone which the Nation can rightfully contemplate in its prosecution; and the moment the object of the war changes from a simple restoration of the Union, as known to the Constitution, to something else in conflict with the guaranties of that instrument, from that moment the war itself changes its character. ...

The emancipation proclamation would not be issues until September 1862, well over a year into the civil war. Incidentally, the emancipation proclamation explicitly did not apply to Union states that still had slaves.

I am inclined to agree with the confederacy's assessment that the North was on the path to forcing abolition. But that is simply not an accurate description of the position of the North at the start of the civil war.

[1]

[0] I suppose unarguable is a bit strong, since empirically there are people who do argue this; but the confederacy at the time was pretty clear on their motivation.

[1] https://www.loc.gov/resource/rbpe.03104100/?st=text