The correct answer is 4) The Constitution seemed to support it.
The option that was not an argument used by Southerners to defend the institution of slavery was "The Constitution seemed to support it."
The Southern States used every argument they had at hand to defend the use of slaves in the plantations. Indeed, the Southern States depended so much on slavery to grow crops that could be exported, Slavery was part of their economy. The cited Biblical passages, social arguments, historical facts, and political issues to defend their arguments over the accusations of the Northern states.
mercantilism increased the likelihood of conflicts between European powers was that it led to dispute over who could trade where, and disputes over the trade agreements themselves, since every country wanted the "best deal".
I believe the answer you are looking for is: "a violent or destructive protest." The government would be most likely to become involved in a union protest that is violent or destructive.
