Final answer:
Mr. Neal and General Thompson justified their objections to slavery at the Massachusetts Ratifying Convention on moral grounds, stating that slavery defied the nation's founding values of equality and liberty.
Step-by-step explanation:
At the Massachusetts Ratifying Convention, Mr. Neal and General Thompson grounded their objections to the institution of slavery on moral principles and the ideals of the American Revolution. They believed that slavery was immoral and in contradiction to the founding principles of equality and liberty. This perspective aligned with William H. Seward's Senate speech, which stated that slavery was repugnant to the law of nature and nations, and although the Constitution recognized slavery, it was fundamentally incompatible with the nation's founding principles. The debate between the North and South over the issue of slavery intensified throughout the 19th century, with Northern representatives supporting measures like the Tallmadge Amendment, denouncing slavery, and seeking to limit Southern political power by reducing representation based on slave populations.
Furthermore, the ratification debates emphasized the conflict over state and federal powers, with figures such as Rufus King attacking the morality of slavery and pointing out that it was against the law of God. The proslavery arguments made by Southerners were to defend their economic interests and way of life, critiquing wage labor in the North and depicting their form of slavery as benevolent. This growing divide over the issue of slavery would eventually lead to larger national conflicts.