Answer:
Fire-eaters.
Step-by-step explanation:
Fire-eaters are the group of pro-slavery Democratic leaders who supported the secession of their states from the Union. They believe that slavery is a necessity and an important part of their livelihood which renders them an enemy of the Northern states' abolitionist attitude.
In the given excerpt from The Mississippi Ordinance of Secession, the declaration is that the longer they stay in the Union, they will only be subjugated, meaning they will be controlled or put under control.
Thus, this declaration will be most strongly supported by the Fire-eaters.