What was the greatest concern for those opposing nullification in the 1830s?

The greatest concern for those opposing nullification in the 1830s was the potential threat it posed to the unity and authority of the federal government. Opponents feared that allowing states to nullify Federal Laws could lead to disunion and anarchy, undermining the Constitution and the rule of law. They believed that if one state could reject federal mandates, other states might follow, leading to a fragmented nation with competing interests. This concern was particularly heightened by the context of sectional tensions and the ongoing debates over slavery and states' rights.