After the Dred Scott decision, Frederick Douglass said he sought to have Americans live up to the principle of the constitution. What did he believe prevented Americans from living up to the constitution?

Manifest
Ablation
Popular sovereignty
Slavery

Frederick Douglass believed that slavery was the main factor preventing Americans from living up to the principles of the constitution. He argued that the institution of slavery was a violation of the principles of equality and liberty that were enshrined in the constitution.