Why did some people in the north support the institution of slavery?

some people in the north feared that if slavery ended, plantation owners would build textile mills in the south.

northerner's did not want the slaves to worry about unemployment like factory workers from the north.

factory owners wanted to bring slaves to the north to work in textile mills.

the textile industry in the northeast was very profitable because of the inexpensive cotton that was produced in the south, as a result of slaves labor.