What did the Radical Republicans primarily seek to protect after the Civil War?

The Radical Republicans primarily sought to protect the rights of African Americans after the Civil War. This faction within the Republican Party was dedicated to ensuring that formerly enslaved individuals received full citizenship rights and were granted equal protection under the law. Their efforts were pivotal in pushing for constitutional amendments, such as the 13th, 14th, and 15th Amendments, which abolished slavery, defined citizenship, and secured voting rights for African American men, respectively.

The Radical Republicans believed that the nation needed to rebuild not only physically but also socially and politically in a way that would prevent the old systems of oppression from re-establishing themselves. They aimed to promote civil rights, enforce the rule of law, and work against the prevailing attitudes of white supremacy that persisted in many Southern states during the Reconstruction era.

In contrast, the other answer choices reflect interests that did not align with the primary goals of the Radical Republicans. The rights of white landowners and Confederate supporters were typically upheld by more conservative factions during this period, while the rights of immigrants fell outside the specific focus of the Radical Republican agenda. Their commitment was largely centered on the integration and protection of African Americans in the post-war society.