Answer :
Calhoun's reference to "the relation between the two races in the Southern section" primarily pertains to the system of slavery in the Southern states. This phrase underscores the intricate and problematic dynamics between the white slave-owning population and the enslaved African Americans. It encapsulates the power dynamics, oppression, and racial inequalities inherent in the institution of slavery.
Furthermore, Calhoun's assertion highlights the fundamental role of race in shaping the social, economic, and political landscape of the Southern region during that time. It emphasizes the dehumanizing treatment of African Americans as property and the entrenched beliefs in white supremacy that underpinned the institution of slavery.
In essence, when Calhoun refers to "the relation between the two races in the Southern section," he is alluding to the deeply ingrained system of slavery that defined the interactions and power structures between white slaveholders and enslaved individuals in the Southern states.