What was the cultural perspective of the North toward slavery before the civil war?

Northern attitudes towards slavery before the Civil War were mixed; there was no homogeneous Northern response to it.  Many Northerners had no opinion on it, but they believed that the right to own slaves was protected in the Constitution as it was a property right.  Some Northerners were against freeing the slaves as the freed slaves would come up North and compete with unskilled natives and immigrants for a finite amount of jobs.  Others, especially in the Northeast, were against slavery altogether.  They viewed it as a moral failing that contributed to the South's lack of industry--why should white Americans be productive if they could get the Africans to do everything for them?  It was only a minority of a minority of abolitionists who saw freeing the slaves as essential as it was the right thing to do for the sake of the enslaved.  James Birney started the Liberty Party as a way for Whigs who opposed slavery to leave the party and not vote for the slaveholder Henry Clay in 1840.  Harriet Beecher Stowe wrote Uncle Tom's Cabin about the plight of a slave family; Stowe never went South to view these conditions firsthand, but her book was taken so realistically that more people came to believe that abolition was the only way to save the soul of the country.  Also, when Congress strengthened the already-existing Fugitive Slave Law as part of the Compromise of 1850, many in the Northeast used state-created personal liberty laws as a way to avoid helping to catch runaway slaves.