who helped shape northern sentiments even more solidkly against slavery in the years leading up to the civil war

Question

was it common sense

Answer 1

That would be the 16th president of the United States, Abraham Lincoln.  He believed that slavery was morally wrong.

 

Common sense had something to do with the Revolutionary War against Great Britain.  This "common sense" is to not be confused with today's definition of "common sense".  But then you probably know that common sense is not so common.