What issues divide the countrey at the end of the era of good feelings

Sectionalism

Explanation:

The era of good feelings refers to the period when most Americans actually have a sense of unity and purpose to work together with all citizens to bring the country forward.

But, Slavery issues create a sectionalism that divided the northern and southern states. The northern states wanted to abolished slavery and the southern states wanted to keep slavery.

In the end, this end the sense of unity between the people which eventually led to the civil war.