Final answer:
Pro-slavery actions in the 1820s included enforcing harsher laws against enslaved populations and legislation like the Fugitive Slave Act of 1850 to maintain the institution of slavery. They also used violence against opponents of slavery, contributing to the pre-Civil War tension.
Step-by-step explanation:
In the 1820s, pro-slavery individuals and groups in the United States took several actions to maintain and strengthen the institution of slavery. In response to slave uprisings, such as the one led by Charles Deslondes in 1811 in Louisiana, which was inspired by the Haitian Revolution, and the anticipated threat of abolitionist movements, pro-slavery individuals enacted stricter laws. For instance, in 1740 following the Stono Rebellion, South Carolina passed the Negro Act of 1740 which prohibited enslaved people from various freedoms like assembling and traveling freely. Later, in 1680, Virginia passed an act to prevent insurrections that forbade enslaved Africans from carrying weapons, gathering in public, and traveling without permission, demonstrating long-term efforts to suppress any potential slave rebellion.
Further, with the enforcement of the Fugitive Slave Act of 1850, pro-slavery advocates backed legislation that severely penalized anyone who helped runaway slaves or failed to arrest them. These actions, coupled with violent measures, including threatening, beating, and killing those who opposed slavery ("D" in the provided options), show the direct efforts made by pro-slavery supporters to maintain the system of slavery and suppress the voices of abolitionists.
Overall, these actions contributed to the deeply polarized and violent climate leading up to the American Civil War, where pro-slavery sentiments clashed with abolitionist ideals, demonstrating the escalating tensions over slavery in America.