[DiogenesLamp]

What Northern workers did worry about in 1860 was the possibility of being replaced by work-gangs of Southern slaves through legal actions related to the SCOTUS Dred-Scott decision.

This is exactly what I was referring to. They were motivated by Economics, not morality.

[BroJoeK]

DiogenesLamp: "This is exactly what I was referring to. They were motivated by Economics, not morality."

Why do you think the two were in opposition?
The fact is that abolitionism had its roots in religious revivals known as "the Great Awakenings", especially the Second Great Awakening, about which it's said:

"Revivals and perfectionist hopes of improving individuals and society continued to increase from 1840 to 1865 across all major denominations, especially in urban areas.
Evangelists often directly addressed issues such as slavery, greed, and poverty, laying the groundwork for later reform movements.[41]
The influence of the Awakening continued in the form of more secular movements.[42]
In the midst of shifts in theology and church polity, American Christians began progressive movements to reform society during this period.
Known commonly as antebellum reform, this phenomenon included reforms against the consumption of alcohol, for women's rights and abolition of slavery, and a multitude of other issues faced by society.[43]"

So Northern abolitionism began in churches as a moral crusade, then later became an irresistible political force when economic concerns raised by the SCOTUS Dred Scott ruling were added to Biblically based moral condemnations of slavery.