In what way did Uncle Tom’s Cabin change the attitude of Northerners about slavery?

They began to view it as a political problem

rather than just a moral issue. The novel highlighted the inhumanity and cruelty of slavery by portraying the brutal treatment of slaves, leading many Northerners to recognize the need for political action to address the issue. It also stirred up greater sympathy and support for the abolitionist movement, further impacting public opinion and ultimately contributing to the push for the abolition of slavery.